The poll results are interesting. They only need to draw in more players than they lose by stopping 4th and going to 5th. Yet just in the number of pathfinder players you beat the number of 4E people who wouldn't switch. Not to mention all the others coming along for the ride. This just might work.
I'm finding the poll response really encouraging for WotC - it looks like they've hit on something here. Now they just need to keep it up.
My group is super-interested in playtesting - I just need to coordinate it with my wife. If THEY want to switch our game to it, once it's released, I'll be game as long as it's a competent system. Everyone's having fun at what we're doing right now, though, at the moment.