As per my post not too far upthread, I think I agree that it is designed to cause confusion.If WoTC had went to a neutral lawyer for advice, I think the advice would be along the lines of:
"It is unlikely that the OGL 1.0 can be revoked. It was clearly intended to be non-revocable.
"However, you can certainly release the updated version of D&D outside the OGL. You can use a new license to do this, as was done in 2008. That will prevent third parties from using material unique to the updated version of D&D."
But instead of a brand new licence, we're seeing this "OGL 1.1" that explicitly claims to be an update, putting it within section 9 of OGL 1.0. And we're seeing an implicit claim that they can somehow revoke 1.0 - they don't seem to have made this claim explicit, but it's clearly what they want readers of 1.1 to think.
OGL 1.1 is a terror weapon, not a weapon designed for maximum legal efficiency. It's an AT-AT not an MBT. In the cause of sowing fear and confusion, it puts WoTC in a significantly worse legal position. A licence drafted to protect WoTC's legal rights and to stand up well in court would look quite different, IMO.
My thought about its relationship to v 1.0/1.0a might be different from yours, though, and I'm interested to work out if that's so.
A party to the OGL v 1.1 agrees, via the screenshot clause, that they are becoming a party to an updated version of the OGL. That suggests, therefore, that they also agree to allow v 1.1 to be used to distribute (etc) their OGC. They also agree that v 1.0/1.0a is no longer authorised by WotC, and hence renounce the right to distribute any OGC under that licence.
A key question is, what is the status of OGC contributed by licensees who are not party to v 1.1. I don't think that they have agreed to have their content distributed by other parties under v 1.1, as those parties (it seems to me) are not conferring on v 1.0a licensees the rights those licensees are entitled to, including the right to choose which licence to use (because v 1.1 parties can't confer that right - at a minimum they have renounced their previous power to confer the right on others to use v 1.0/1.0a).
So I'm not sure that WotC have failed to protect their own rights. Because anyone who enters into a new licence with them now, ie via 1.1, is passing through a one-way door (I think, as per the above). And those parties bring their own OGC with them, but cut off their membership of the 1.0/1.0a ecosystem. Or at least perhaps some of their OGC - because those parties cannot both enter the 1.1 ecosystem and honour obligations they might owe to parties to 1.0/1.0a, and so perhaps can't bring all of their OGC with them - only OGC that is licensed by another 1.1 party.
Which to me seems to fracture the 3PP ecosystem in a much weirder fashion than I think the GSL did, or than your proposal would.