I agree that the complaint of multiple universes being confusing doesn't hold much weight. The concept of parallel Earths has been a common idea not only in comics, but throughout all fiction, for the past several decades and beyond. It's really not difficult to grasp, even for new comic readers, especially if you paste a big EARTH-N label on the cover, or even make it the title as they did for Earth-2. Now, other people may not like the concept for other reasons, but what the heck, we already have these parallel Earths, we might as well utilize them.
That being said, I would love to see an Earth-3 book starring a slightly revised version of the Crime Syndicate, as more of a group of greedy, dangerous protectors, rather than villains with plans of world domination, and a name change would be needed as well.