(warning: a text wall approaches)
Mike Mearls (just in case you don't know that's the guy who's probably going to be in charge of making 5th edition) has a weekly column and is using it for market research, asking questions that basically boil down to stuff like: "do you like that D&D's based around minis now?"
The current question asks if Fourth and every other edition (including basic!) is "Too complicated", "Just right", or "Not complex enough".
The lifespan of the other WotC editions, 3 and 3.5, was about four years average for each. So if Fourth follows suit, then it's got just over 1 year left. That might be a little soon but editions don't happen overnight, they're probably working on it or at least thinking about it. Especially considering Fourth was a disappointment for them, in how it split the market with Pathfinder.
The column is focusing on D&D history, how it's changed and it started off with an appeal for unity. It sounds to me like 5th has a chance to be more classic friendly, or at least they're using the column to explore that possibility. This Mike Meals fellow apparently does play some TSR D&D every now and again. (And let's not forget the redbox, somebody is pushing for classic even if it's not coming through to the final product.)
Hopefully it's not just WotC fans voting, being more likely to stumble over it on the WotC website than OSR or former players.
This week I voted that 3rd and Fourth editions were "too complicated" and that 1st, 2nd and basic were "just right".
The results from last week's pole were kind of grim, but it was a bit of a loaded question. It was about the possibility of removing feats and skills from the game (!) and the winning result was "I'd be bored doing the same thing over and over again, round after round in a fight". Wow...
In that poll I voted for "I’d be happy that I can have an effective character without the complexity". The column is really harping on complexity. I worry there are too many WotC fans now who've been trained to love complexity and I hope WotC realizes the key to a popular D&D is B/X style elegant simplicity.