Baseless character assassination is distasteful.
"Character assassination" seems like hyperbole for that rather mild post by
@Reynard lol.
Also, you're failing to understand that it doesn't really matter what his "level of involvement" was with the the OGL issue - the point is he neither said anything at the time, nor has said anything since, to indicate he considered it a "bad idea".
At best we can probably say he values his job and income enough that he doesn't want to rock the boat - that's fine, that's true for many of us, but when a company is being naughty, that does tend to put one on the wrong side of things.
I suspect pretty much none of WotC's actual D&D designers had much influence on the OGL decision-making.
I imagine he'd stick around to try to influence the direction of the game in whatever way he could. I get the feeling from the way he's talked about it that the game means that much to him.
I have to say, I've never really bought this line in the countless situations where people use it, not when they've been at place for decades without that change happening anyway. I'm sure plenty of people sign up to do precisely this - but if you're not seeing the change you want within a few years, you're likely leaving. If you're not seeing the change you want within a decade, and you're sticking around, well I think you're probably fooling yourself about why you're there.
Did any heads roll over this?
As far as we can tell absolutely no heads rolled.
It's a fair point that WotC wouldn't tell us, but the reality is, if anyone major had gone, the D&D nerd community would have picked it up by now, and they haven't. So it's safe to say no major heads rolled. If any heads did roll it was probably the leakers, not the people who thought this was a good idea, because it was clearly thought to be a good idea at a very high level, given the communications WotC made.