So, let me get this straight. They are designing D&D 5E to be the 'one ring' of D&D editions? No doubt in an attempt to stop the fragmented market totally killing them. Which it undoubtedly is and would continue to do so with every release. I can see the reason for the goal, but I think it's a lofty one.
An edition with an OD&D-like base that then, in a modular fashion, could grow into something that is more 2E and 3E like I could sort of see. None of them would be exactly like any of those editions but I could see the style intent and general widgets being similar. I'm not sure you could extend such a module approach to 4E. It seems that would just need so much new stuff it may as well be a new game...again.
Also, it's interesting they put what version of these modular rules the character uses as a player choice. Very strange. Are they really suggesting someone could be interfacing with the game in OD&D mode while someone else has opted for 2E mode?
It's going to be a masterpiece or a complete disaster. Nothing in between. They vitriol during the games development may also sour the whole idea before it hits the shelves. Watershed moment me thinks.