pawsplay
Hero
We will never know. Here's the thing; 3e was successful, and 3e had the OGL. So it must have been at least not a terribly bad thing. In fact, I doubt 4e would have taken the form it did if 3e was not successful enough to saturate the D&D market. But WotC never really embraced the OGL.
The first thing that happened was they backed some critters out of the SRD. Despite being prohibited by the OGL, just about everyone decided to be gentle about it and allow Wotc the "takeback" on what they later branded as "iconic" D&D creatures, including the displacer beast, which was substantially influenced by the coeurl in its appearance, and the illithid, which was inspired by the cover of a Lumley book (IIRC).
MMII had two OGL critters in it. WotC trumpeted the OGL in that book, but I noticed something interesting. They didn't use the OGL to publish those critters, they just got permission from the publisher and then declared them OGC. Look at the copyright declaration in the license. Also, of course, WotC declared none of their own critters to be OGC.
Later on, psionics and epic rules (including 3.5 updates) made it into the SRD. Once WotC apparently realized they needed some way to start offloading d20 Modern books, they opened up d20 Future and Urbana Arcana, but it was too little, too late.
So it's hard to draw conclusions about how awesome the OGL could have been for WotC. All we can do is observe that even with their half-hearted commitment, things worked out pretty well. As to the whole GSL thing, well that's just too bad. REally, the "safe harbor" was there just as much to protect WotC's IP and save money on lawyers as to help third party publishers, but someone apparently did not get on board with that philosophy.
