You know, I love 4e. I GM several games and love playing PCs when I get the oppurtunity, but I rather WotC Developers to stop trying to do wacky things and go back to their Core worlds and rules and perfect them.
I think of what they are doing with trying to put out a fire with a leaky bucket. Yeah, they might be making progress but it would go alot faster if they plug the holes instead of ignoring all the wasted water. I HATE how they fix the rules by putting now new builds and feats instead of going back and just fixing things. It leaves the game spread all over place like the wasted water in my metaphor. We have races that are not updated and we have obsolete feats. We have class builds that are unusable. We have a treasure system that is only half updated. We have a new focus on the classic parts of DnD but with little support for that which came before.
Does this make me want to switch games or editions? No, I still think 4e is best at alot of things. It just annoys me that instead of seeing any work done for what affects my game, I see Fortune Cards, Board games, and Vampire Classes.
I do have an answer though. Do BOTH! Put someone in charge of updating what has come before, along with inventing of new crap that might attract more sales.
I'm not going to argue many points you made, but I think you're pointing out something you're not aware you're pointing out. The fact that a "do both" answer requires more manpower. Something everyone says WotC has been lacking for a while.
I think the designers, like Mearls and the others do the best the can with what they are ASSIGNED to do. And if it was to constantly look back on what they did, we'd be up to Player Handbook 1 Revision 34. No other books. No campaign settings or Power books. Just "perfecting" one thing.
Cards, Vampires and Boxed Sets. Those are what's popular in the gaming and non-gaming world right now. If that's what it takes to get "Such-and-Such Campaign Setting From 2nd Edition" or what have you so be it. Business is business.