The OGL brought so much goodness in the way of Third Party Modules. I will never understand why WoTC decided to hamstring something that did so much good for RPGs in general and made D20, and by extension DnD so popular.
Admittedly the OGL is much more open than the GSL, and we may have to ask certain 3rd party developers of 4e material to weigh in, but as it stands now with the current iteration of the license, is the GSL really the reason 3rd party 4e support is so sparse? I don't believe it is.
See, initially the leading 3rd party providers were waiting for the GSL, and waiting and waiting, and then the first version was very restricting to established companies with employees and had no real guarantees (maybe this current version, too, not sure), and ultimately they all jumped ship, developed their own stuff, and are currently riding some very successful waves. I think the main reason we don't have 3rd party 4e support has less to do with the current GSL, though, and more to do with the lack of developers and design teams not dedicated to some other game.
The next generation of D&D 3rd party designers needs to emerge. That's not to say there aren't some very fine freelancers and third party developers, there are, but there has to be, in my opinion (and my ardent hope) a lot more. I figure here is as good a place as any to find them, just another reason for the survey.
There should be more serious discussion on fan-made and grassroots third party support, and actual projects and collaborations. Modules are a good place to start. I know the talent is out there, we just have to find the willingness, and work together to make what 4e gamers want and need, original content, unique content, providing new efforts to add to the works of WotC, EnWorld, Kobold Quarterly, Deus Ex Machina, Save Versus Death, etc. I welcome that sort of discussion, that sort of effort, and want to be part of it. I never experienced the freedoms of designing under the OGL, I'm not concerned about what was lost between, but I am interested in providing content, and I don't think the current GSL is so nightmarish that it is impossible, if the list above says anything, but I'm not any sort of licensing expert. I don't feel overly deterred by the GSL, though.