The tack you want to take is not that rolling back solutions is progress, but that progress is bad, and that things like class imbalance are what the fanbase /wants/.
Or maybe class imbalance is something most players don't notice or care about. Subjects of interest to system wonks on RPG forums don't necessarily correlate to the subjects of interest to the much wider group of fans (especially large for D&D) who don't participate in forums.
5e is directed primarily at longtime fans, and quite effectively so, calling back the ancient feel of early AD&D. Why, I was just reviewing HotDQ as I'm going to run it at Encounters, and I was struck by the charming, nostalgic archaisms, like random encounters of random numbers of monsters, that it lead with. The way Mearls & co talk about appealing to new players (and the way Encounters, aimed somewhat at new players, is being set up) also speaks more to appealing to what longtime players remember of being new, than what actual new players might need out of the game.
Is there something inherently unappealing to new gamers about random monster encounters? Just because something is appealing to long-time players doesn't mean it's unappealing to new players. Some of the stuff people enjoyed in D&D 25 years wasn't because they had no choice or didn't know any better - they actually enjoyed it because it was fun. And it can also be fun for new gamers today.
If 4E really was as appealing to new players as you suggest, I doubt it would have been shelved by WotC. They don't care who is buying their books - old fans or new. In my experience, character generation in 4E (pre-Essentials) was simply too involved to make it very accessible to casual gamers. As WotC themselves have admited, for more than 10 years now WotC has catered too much to hardcore gamers. They lost sight of what most people say they want out of a tabletop RPG, which is to generate fun stories with their friends. Too much crunch is a barrier to adoption. Essentials was an effort to make the game easier to get into, but it was too little too late.