I missed this before. Just adding to @Steel_Wind's reply:Questions for the contract lawyers here.
Does the situation around OGL 1.1 fit the definition of coercion for designers and publishers?
Does the situation around OGL 1.1 fit the definition of undue Influence for designers and publishers?
Does the situation around OGL 1.1 fit the definition of unconscionability in the terms given to designers and publishers?
Does OGL 1.1 fit the definition of misrepresentation as it claims to be an open license, but does not fit the generally accepted definition, not being copyleft?
If yes to any of the above, does that undermine the ability of WotC to enforce OGL 1.1?
I don't see any coercion here, only offers - and why would 3PPs want to argue coercion in any event? They want to uphold and enforce their contractual rights under the OGL v 1.0/1.0a, not argue that they were coerced into becoming party to it.
The same point about not wanting to vitiate or read down the contract applies to your other questions too. But setting that to one side, and replying from the perspective of the Australian law that I am familiar with:
There is no undue influence here. These are all arm's length transactions between informed business parties. (In Australian and English law undue influence can operate in contexts other than estates, but it requires showing that someone's mind was overborne by the will of another. Nothing of that sort is happening here.)
There is no unconscionability that I can see. WotC is not taking advantage of its position vis-a-vis other parties to unfairly obtain a contractual benefit.
And WotC is not misrepresenting anyone about its contract, as far as I can see. Everyone who (to date) has been offered the chance to become a party has been shown the terms.
More generally: it doesn't serve the interests of 3PPs, as far as I can see, to argue that WotC is not entering into contracts in a valid fashion. This is at its core a straightforward case about contractual rights: 3PPs who have become party to the OGL thereby obtained contractual entitlements and contractual powers, as well as subjecting themselves to contractual obligations. WotC is now threatening to proceed as if those rights don't exist (eg by suing licensed parties for copyright infringement). The most obvious solution is for 3PPs to assert their contractual rights.