What I am about to argue assumes that WotC/Hasbro has decided to declare Nuclear Lawfare. You are probably legally right. You would also be served a Cease and Desist letter when you publish your OGL 1.0a content, if anybody will let you publish it, that is (DriveThruRPG will likely not, KickStarter will probably not. Am not sure how you get it published but let's assume you do). Let's assume your content is WILDLY successful! Let's assume you decide to tell WotC/Hasbro to shove their C&D and move forward. Now you are served with a lawsuit and you have to come up with at least $500,00 to pay for the first year of discovery and that will likely draw out to a second year. Meanwhile, WotC/Hasbro has judge shopped and file a motion to stop you from publishing the content until a decision is made. Now you are without income to fight this in court and we're into year 3 where the motions start. motions daily. You are buried under so many legal documents that it now costs a cool $1 million every two months to fight this lawsuit, and there appears to be no end in sight for these motions.
WotC/Hasbro doesn't care what the likely outcome would be in a court because they have the funding and legal department to make certain it never sees the inside of a court,