This is moderately interesting to Avengers/Marvel fans...........in 1989 Marvel conducted a poll where readers voted for their favorite candidates for Avengers membership. A crappy quality scan of the results pulled from a letters page can be seen here (just incase you thought i was making this up).
The results for the Favorite candidates for Avengers Membership in 1989 were:
1. Spider-Man (375 votes)
Spider-Man was the top vote with nearly triple the amount of votes of the runner-up! He had been teased and offered membership before and he seems like the obvious choice for a member. In fact he became an Avenger within the next year in The Avengers (1963) #314.
2. Daredevil (136 votes)
Daredevil came in second place in the poll. Daredevil is another character who had been an ally to the team and offered membership in the past but never accepted. Despite being the runner-up in the poll, Daredevil still didn't become an Avenger until two decades time in New Avengers (2010) #16.
3. Ant-Man (78 votes)
Of course referring to Scott Lang, the second Ant-Man, he was an interesting case that he wasn't an Avenger at this point despite having hung around the Avengers and Iron Man almost religiously under David Michelinie's pen. Despite being a consistent ally to the team, it wasn't until over a decade later in Avengers (1998) #52 that he was finally recognised as an official member.
4. Doctor Strange (53 votes)
In 4th place was Doctor Strange, who like most these guys was an on-again-off-again ally and after the dissolution of the Defenders a year or two earlier, he probably could've migrated to the Avengers quite easily. Yet Doctor Strange didn't join with the Avengers until much later in New Avengers (2005) #27 almost 20 years after this poll.
5. Wolverine (51 votes)
Oh lord, you knew this was coming. Wolverine was hot off his first series by Frank Miller and his ongoing had just made it's debut. The character was immensely popular but despite that he only scored fifth place. Not really having much interaction with the Avengers or much point in him being a member he didn't join forces with the team until fifteen years later in New Avengers (2005) #6.
6. Spider-Woman (50 votes)
Spider-Woman, in this case Julia Carpenter, was introduced only 3 years before the poll but in that short time she found herself part of Secret Wars, Freedom Force and appearing as guest star in several big books. Despite ranking below a cast of other candidates, she did become an Avenger shortly after this poll in Avengers West Coast (1989) #74.
7. Silver Surfer (46 votes)
Silver Surfer, much like Doctor Strange, could've easily taken up a place with the Avengers after the Defenders disbanded during Secret Wars II. In fact, with regards to the finale of Secret Wars II, it may have even been testing the waters to see if he gelled with the team since the Surfer was a big player in the (excellent) Molecule Man epilogue featured in an issue of Avengers. Nevertheless, to this day, he still hasn't joined the Avengers despite still being a rather obvious big-name candidate.
8. Battlestar (44 votes)
A lot of you might ask "who the heck is Battlestar"? Well, this poll was conducted a few months after the epic long-running story on Captain America and one of the loose ends was a character called Battlestar. Former partner to John Walker as Captain America, Battlestar had no place to go and dropped off the face of the Earth shortly after only having a brief revival in Silver Sable and the Wild Pack. The altruistic and less abrasive Battlestar would've been a better choice for an Avengers team than Walker who had just become an Avenger himself. Battlestar was optioned for membership and befriended the Falcon, but his relationship with the team - much like the character himself - was dropped.
9. Speedball (34 votes)
Speedball was 1988's "hot character". Created by legendary artist Steve Ditko, he launched out of Amazing Spider-Man Annual and then quickly got his own ongoing which ended after ten issues. All of this in the space of a year. With regards to the time, it's not exactly surprising that one of that year's big characters managed to crack the top ten. Speedball hasn't joined the Avengers yet but he has ties to the team with regards to his early involvement with the Avengers Academy.
10. Doc Samson (29 votes)
Rounding out the top ten is another some what odd choice. Samson's involvement with the Avengers had been minimal but it's pretty easy to see the logic behind including him in the Avengers. With Samson you get a Hulk-type superhero without the problems that come with the real Hulk. Despite it making sense, Doc Samson never did join the Avengers and with him being dead and another 5 Hulks to choose from nowadays, it's not looking likely he ever will.
11. Sandman (28 votes)
Former Spider-Man villain Sandman ranked at 11th. Sandman was another character who had recently underwent some major changes - namely his reform that had been chronicled across various Fantastic Four and Spider-Man comics and led to alliances with Silver Sable, Hawkeye and the Avengers. The new direction for the character was working well and a miniseries starring the former villain was even planned around this time which sadly never got off the ground. Despite not making the top ten, Sandman found his way on to the Avengers within a year in The Avengers (1963) #329.
12. Shroud / Punisher (27 votes)
Avengers ally Shroud and another hot character of the time The Punisher tied at 12th place. While the latter hasn't joined the Avengers and hopefully never will, it's understandable that he would end up with a few votes in a poll among readers - particularly during the character's heyday. The former however has a bit of a complicated history. A long-time ally, Shroud was offered a spot as a founding member on the West Coast team but declined. He was later revealed only a year earlier to have been discreetly assisting the team from the shadows all the while. Subsequent creators believed him to be an Avenger whereas nowadays it's been swept under the rug and he's not considered one. As it stands, neither characters have much chance to be an Avenger, with the former rarely appearing and the latter completely unsuitable for the team.
13. Firelord (23 votes)
Much like Shroud, Battlestar and Spider-Woman; Firelord was another character who had recently made a big splash in the Avengers family of books. He surfaced amidst Secret Wars II and after the infamous fight with Spider-Man, Firelord allied with the Avengers for several issues to battle such space threats as Nebula, Skrulls and the Beyonder. It seemed incredibly likely that he was going to join with the team but instead the former herald of Galactus left alongside Starfox to investigate Nebula's claims about Starfox's heritage. Other than during the Infinity Gauntlet, Firelord hasn't really mixed it up with Avengers since.
14. Stingray (19 votes)
Stingray, like Ant-Man, had been hanging around the Avengers for so long it was easy to mistake him for an Avenger. Owner of Avengers Island/Hydrobase - their then-current headquarters - Stingray usually found himself thrown into adventures with the team. Even though he ranked at 14 on this poll, he still became a full-fledged Avenger within the next year in The Avengers (1963) #319.
15. Giant-Man / Jack of Hearts (16 votes)
The second tie saw Giant-Man (or as he's better known Black Goliath) and Jack of Hearts with 16 votes each. Giant-Man had been another Avengers ally around this time and had helped the Avengers get their west coast team off the ground and even more recently had joined with Mockingbird's faction of the West Coast team during the Evolutionary War.
Jack of Hearts on the other hand had limited interaction with the Avengers although he had been Iron Man's sidekick 10 years earlier and the character had just received his own miniseries, but like a lot of these characters he had no where to go. Sadly, that was the character's downfall, he didn't really appear anywhere for a long time although he later became an Avenger over a decade later in Avengers (1998) #38.
16. Colossus (15 votes)
With 15 votes, the X-Men's Colossus might seem a bit of an odd choice but it's worth noting that he had only recently rejoined the cast of X-Men following him being incapacitated by injuries during Mutant Massacre. And even with his return, it wasn't clear he was going to become a full-fledged member again. Ultimately he did following the team's alleged death at the end of Fall of the Mutants, but if he didn't show up to "die" with them then the Avengers would've been a good alternative for him to offer his strength. Colossus never did join the Avengers and following current events it's not looking likely he ever will.
17. Cyclops / Nomad (14 votes)
Tying with 14 votes each is X-Factor's Cyclops and Captain America's pal Nomad. The former has always been one of Marvel's most iconic and popular characters and he always could've easily slotted in with Earth's Mightiest Heroes if not for his leadership duties with the X-Men or as it was then X-Factor.
Nomad on the other hand was another character who was at an awkward crossroads during this period. He had only recently stormed out on Captain America calling him as much as a pussy and hadn't been seen for a while. He eventually resurfaced spinning off into his own ongoing series but he made little interaction with Avengers afterwards sans Captain America, Falcon, US Agent and D-Man.
Current continuity, much like in the case of Colossus, makes it unlikely that either will be optioned as candidates. For starters one of them is dead.
18. Firestar / Beta Ray Bill / Black Cat (13 votes)
Firestar, like her future New Warrior teammate Speedball, was another hot new character of the 80s. Actually, she was probably better known as one of Spider-Man's Amazing Friends and her appearances in the comics were pretty scarce. But like Speedball, she was a character who Marvel had gave a slight push to and she had her own miniseries not long before. She did eventually become an Avenger ten years later in Avengers (1998) #4 alongside another New Warrior and her then-boyfriend Justice.
Beta Ray Bill was also a fairly recently introduced character over in the pages of Thor. With Thor coming and going regularly due to the exploits in his own book, perhaps Beta Ray Bill couldn't been a better Thor for the Avengers? We've still never really seen Bill mix it up with the Avengers.
As for Black Cat, she was offered membership during Secret Wars but following her break-up with Peter she didn't really mingle with the superheroes much. She would've been a good addition around this period as she was also infrequently in Spider-Man's book due to the aforementioned break-up.
19. Human Torch / Rogue / Frog-Man / Nick Fury (11 votes)
A 4-way tie at 19. There's not a lot to say about most these guys and their connection to the Avengers. Human Torch is still the only member of the Fantastic Four who hasn't been an Avenger - although worth noting shortly after this poll the Original Human Torch became an Avenger although that was purely coincidental.
Rogue, like most X-Men characters, was hot property in the late 80s and had made her first appearance in an Avengers comic which gave her a bit more stake to the Avengers claim than some other X-Characters. Nevertheless, it's not surprisingly that it took them nearly 25 years to get around to adding Rogue to an Avengers roster.
The goofy Frog-Man had been guest-starring in various books since 1982, managing to get by on his own luck rather than skill. He was a great comic relief character and in fact recently he did ally with the Avengers during Spider-Island.
Despite media adaptations Nick Fury has never had much to do with the Avengers as a team, although he did and will again play a part as an ally to the Defenders. With that team's recent demise in 1986, Fury like Surfer and Strange could've been transplanted over to the Avengers. But, it's understandable why most these guys never really became Avengers.
20. Puma / Red Wolf (10 votes)
And in last place with 10 votes each are two oddly similar characters. Puma was another character who had recently been introduced as an adversary and sometimes ally to Spider-Man. After a convulted and ridiculous inclusion as a part of Secret Wars II, it seemed Puma was destined for more than just chasing Spider-Man around. Seems no-one other than 10 people thought so and Puma stayed in the Spider-books mostly from then on out.
Red Wolf on the other hand first appeared way back in the 70s and became an ally to the Avengers before spinning off into his own-short lived book. He disappeared for a while after that before joining up with the Rangers. Although, he wasn't very relevant at the time of this poll, he had always seemed like a loose end. He always seemed like someone who was intended to join the Avengers but due to writer change-overs never did.
Both characters could've made interesting Avengers but I doubt they'd be at the top of anyone's wish lists.