Did the OGL benefit by having the D&D ruleset published under its name? Absolutely.
Is the OGL perfect? No. Heavens, no. Almost from the beginning, the "Attribution" portion of its viral nature has been a beast (with ever-expanding Section 15's) and I for one am *still* appalled at the general laxity with which the "You Must Clearly Identify What is Open Game Content" is treated (since for a great many publishers, I could say their designations makes it obvious that their understanding of "Clearly" is some new definition of the word with which I am not familiar).
Apart from the fact that I do not like the kludgy Section 15's (how I would have solved it: If you take material from a source, you need only attribute that source, not reproduce its section 15 in its entirety - while this takes away credit "downstream" I think it's preferable to the alternative) and preferred a clearer stance on PI/OGC especially with regard to clarity (not quite sure off the top of my head how I would have solved that one; limiting PI designations to, say, registered trademarks only would solve the problem but is probably too harsh).
So there... there are the flaws I see in the Open Gaming License... that in one case it is too tight and inflexible (section 15) and in one case it is too loose (clear designation).
That it is viral I do *not* see as a flaw. In fact, I see that as its primary FEATURE, not as a bug. From the perspective of WotC, the OGL was there to allow support for - and thus increasing feedback into - D&D, via the "Skaff Effect." While the OGL has had the side effects of allowing entirely new products to be birthed (e.g., the True20 system) that do not directly feed D&D, I think that, by and large, support for D&D was in fact the largest thing it accomplished, and the Skaff Effect probably kicked in well.
With my "gamer" hat on, I am glad that the 3E/OGL mix forever put D&D - or at least one incarnation thereof - beyond the reach of corporate control and vindictiveness on the scale Lorraine Williams(?) attempted. D&D is now free to die of "natural causes" - not enough GAMERS supporting it - rather than of "unnatural ones" (its owner ceasing support/going out of business, etc.)
Now I hear that the GSL may contain clauses to try to force people to abandon the OGL. I happen to believe strongly in Open Source ideology, so I'll say I'm not thrilled that this is even on the table. In my mind, the proper thing to do would have been to go back and "fix" the problems with the Open Game License, then extend a new license, akin to the d20 license, but for 4E, to go along with it and release the 4E SRD-equivalent under the new-and-improved OGL. From a practical, business standpoint, I understand why this is on the table at WotC... but it doesn't make the idealist in me take it the news any better.
ALL THAT SAID, I am reserving final judgment on the GSL until I actually get a final copy in my hot little hands. Until that happens, the hue and cry and handwringing is at best premature and at worst unnecessary. I like to worry about what IS the situation, not what MIGHT BE the situation. Since there are far mor "MIGHT BE'S" than "IS's" it cuts my worry down a lot.
