I voted for not sure because ... I'm not sure.
My original plan was to buy 4E and see if it was worthwhile converting my games (and investing in the coming round of source books), but as I've said in other threads, I'm liking the sounds of things less and less all the time.
If there is no OGL (or GSL) it would be one more thing that would make me hesitate. Although the OGL and d20 licenses produced a real mix bag of third party support, the cream did eventually rise to the top.
I'm also a big fan of Open Source software and seeing an Open Source style license applied to my favorite RPG was one of the cleverest things to come out of the 3E move. The OGL and d20 licenses really did create a massive space or mind share in the RPG marketplace. Many other RPG systems were forced to include d20 conversion rules just to survive. I'm sure Wizards benefited from the huge space that opened up since most of it fed back directly into D&D.
Switching to a more restrictive GSL (or completely closed) makes me less interested overall in committing to the new system for the long run. Sure, I might possibly buy the rules at some point to have a look, but I'm less likely to stick with it because (a) I really like open source and (b) there a lot of really good designers outside of WoTC who may be forced to continue to work with the older OGL or perhaps spawn off their own completely different systems.
At this point, about the only way I'm likely to stick with 4E is if it surprises me and is an incredibly good system. I suspect that is not the case though - it sounds like it might be fun for a while, but that it wouldn't hold my interest long because it has swung too far away from the simulation side over to something that feels too much like a combo between the D&D minis game and a game and some kind of MMORPG.