In the same vein as Merc's thread, will 5E draw in much of the 3.XE/PF crowd?
Short answer: No.
Long answer: The 3.X/PF crowd has already demonstrated that they're fundamentally satisfied with the game they're currently playing. If they're dissatisfied with certain areas of the game, they've probably already made the necessary adjustments to fix them. They've spent years achieving a mastery of the system and that system is the most supported RPG system in history and continues to receive active support with great frequency and of very high quality. Nor will they have any problems finding players, because the pool of available players is huge and the Paizo maintains a very large system of organized play.
So... how does WotC compete with that? They're going up against the entrenched values of the time and money people have invested in the system already, which means they have to leverage other competitive aspects to provide a greater value than the status quo.
Quantity of support? Nope. It took a decade to build up the existing library of 3.X/PF support and there's no realistic way for WotC to even catch up to that.
Quality of support? Paizo achieves a gold standard. If WotC significantly improves the quality of their output, they could realistically hope to
match Paizo, but they can't actually value-add.
Improvements to the system? The problem here is that there is not really any deep dissatisfaction with the 3.X/PF system among 3.X/PF players. Oh, we all have things we bitch about. But the only thing we really all agree on is that there's something wrong with high level play either in terms of power disparity or complexity. And everything else is usually a trivial patch. Even if WotC released "3.X, but better!" it's not really clear that they can achieve enough "better" to get people to abandon [notranslate]Pathfinder[/notranslate] at this point. They might have slightly better luck getting people who stuck with 3.X to simply upgrade (like Windows XP users skipping Vista and going straight to Windows 7), but this is really an academic point because it's clear that this isn't what the designers of D&D Next are looking to deliver.
Digital tools and support? This might work, but WotC has proven itself almost completely incapable of delivering digital support for their games (and just abandoned the digital table) so it's unlikely to actually happen.
They need an edge. And I'm not seeing where they get it unless Paizo just completely falls apart in 2013.