A thread at the Paizo messageboards that inquired about Paizo's interest in the revised GSL has been responded by the staff that they will not be producing any 4E-supported material.
Vic Wertz, Technical Director of Paizo said that while it is possible for licensees of the GSL to produce both OGL and GSL content, it was also very risky as stated in the GSL FAQ. He also said that the GSL had come at a poor time for Paizo.
This set of revisions to the GSL falls squarely into the categories of both "too little" and "too late" as far as addressing Paizo's concerns.
James Jacobs, Editor-in-Chief of Pathfinder echoes Paizo's sentiments about the GSL and 4E with a statement on Paizo's stance and that it would not make 'good business sense' to jump on the bandwagon at this time.
At this point in time, no. Paizo's not interested at all in producing 4th edition content or conversions.
We're launching the PF RPG this August, and it's just not good business sense for us to try to support other games at this time. Furthermore, the 4th edition rules are dramatically different than the 3.5/Pathfinder RPG rules. None of us here at Paizo are overly familiar with the 4th edition rules, and I, as Editor-in-Chief, am one of the least familiar with those rules of all of us simply because I've not really had time to tear away from Pathfinder-related stuff to branch out into playing other games, be they 4th edition D&D, Mutants & Masterminds, Traveller, or whatever. (Although I do try to make exceptions now and then for Call of Cthulhu!)
The point is, though, no one at Paizo is an expert at the 4th edition rules, and in order to become experts at the rules so that we could produce products we wouldn't be embarrassed to see in print for all the errors, we'd have to invest a LOT of time getting up to speed. Time that would take away from producing the Pathfinder/3.5 products we're already short on time with, but that we do well and that are financially successful. Personally, I agree with Erik in that the 4th edition system isn't appropriate to the types of products and adventures I'm interested in producing for Paizo—both from a rules stand point and CERTAINLY from a flavor standpoint.
Honestly, at this point, something relatively catastrophic would have to happen before Paizo considered switching over to 4th edition.
Pathfinder RPG (and by extension due to its compatibility, 3.5) is the game we'll be producing content for.
When asked about the Pathfinder OGL and SRD, he also comments that they hope it would be up before or during GenCon when the Pathfinder RPG is released.