I feel that other than Zoom, pretty much all of the Flash's enemies are really underrated. Villains like Captain Cold, Trickster, and Captain Boomerang are viewed by a lot of people as being lame and weak.
" Well most of them were pretty lame for a very long time, they got more cred around the time they killed a Flash. "this is the best answer for many many years they were gimmicky and dull. with the exception of Grodd whom has always been a top tier DC villain. but in recent years yes the Flash rogues have really carved a nice niche for themselves.
I always loved how Batman and Barry Allen would argue about who had the better rogues, so yeah, I don't think people give them enough credit. I have to say, I do love how they're being written and presented in the New 52. Definitely more than just your stock villains, they have depth.
They are considered lame because unlike just about every other collection of villains, they have that code that forbids them from turning really nasty, therefore they aren't considered as dangerous as, say, the Bat-foes.
DC hasn't helped ofc since most of DC's villains don't seem to think very much of the Rogues either.