A new OGL does nothing for prior releases, unless those companies/people re-release under the new version. Which they could already do right now with the CC. In other worse, there is NOTHING that can return the situation to the status quo prior to what happened. You can't make people re-release material under the new OGL. Releasing a new OGL doesn't return all those prior books to being under the that new OGL. Some of those companies don't even exist anymore or involve people no longer in the industry.
The OGL has this clause in it:
9. Updating the License: Wizards or its designated Agents may publish updated versions of this License. You may use any authorized version of this License to copy, modify and distribute any Open Game Content originally distributed under any version of this License.
To me, that reads that should they create an OGL 1.2 with the word "irrevocable" added to clause 4, future users could use the irrevocable version of the license to copy, modify, and distribute any OGC originally distributed under 1.0 (a). But I'm not a lawyer.
You left out a pretty important reason to go with the ones that you mentioned for why people are justifiably skeptical over a statement like "we did wrong" ... Namely the fact that this was the second time they tried to kill the OGL. The GSL was their first failure at doing it right. OGL 1.1 was the second and some of the initial reports on it were dismissed on the idea that nobody at such a large company would be stupid enough to try a second bite at it after the GSL did so much to help drag 4e down. Saying "we did it wrong" implies that there is a right way and leaves open the door for a third try at figuring out how to accomplish the goal of murdering d&D's open license "right".
The major difference between the GSL and this is that the GSL was fair. Well, the license itself was bad, but it was handled in a pretty fair way. The d20STL (the license allowing you to use the d20 logo to indicate compatibility with D&D) was never promised to be permanent, and had its terms changed multiple times as the need arose, and even included provisions for what'd happen if it was canceled. They didn't touch the actual OGL or SRD, that remained sacrosanct – they probably never expected that anyone would manage to produce a viable alternative based on the SRD (likely the expectations was that someone might make a game about as successful as Arcana Unearthed or Mutants & Masterminds – fine for a smaller company, but wholly beneath WOTC's notice), but Paizo sure did.
And from what I recall at the time, the overall reaction was more "Well, that sucks" than the "How
DARE they" the latest attempt provoked.