There is
no chance that a 4th edition will mark a return to an earlier edition in actual game mechanics.
It
might be like the earlier editions, though, in trying to be more modular. Although not explicitly designed this way, you could easily ignore large aspects of 1st edition (as well as the RC DnD rules, and I assume 2nd edition too), and add optional rules to it, without "breaking" the game. On the other hand, eliminating some feature of 3rd edition -- e.g. feats -- or radically changing some other feature -- e.g. the combat system -- can cause the whole system to collapse. (I am not saying that it is impossible to do these things in 3.x, just that it is much more difficult than it was in earlier editions).
The rules of 3.x are much more interdependent than they were in earlier editions. It would not surprise me if a new version of DnD tried to be modular, in order to better please
both players weary of the complexity of 3.x (e.g. the seemingly endless numbers of modifiers to skill checks, the slow and detailed combat system, etc.) and those who love additional complexity (e.g. want more feats, more complex combat, prestige classes, etc.).
Anyway, if you really prefer the earlier editions,
nothing is stopping your from playing them! (I recently played an "old-school" RC campaign -- and loved it!) As mentioned earlier in this thread, Dragonfoot supports an active OOP DnD community (including free downloads of new material for 1st edition ADnD). The OD&Dities site produces new material and a very good fanzine for people who play the "Basic/Expert" or Rules Cylcopedia DnD systems.
And finally, as Krieg and Turanil have already mentioned, TLG is coming out with "Castles and Crusades," which attempts to recapture the "feel" and simplicity of earlier editions (no feats!), while using the d20 mechanic.
