Here are a few ideas that would both please customers and you.
1 If its not possible to make Dx10, maybe you could consider giving the game to people purchasing DX11. There have been partnerships between hardware makers, i can for example tell you some headphones were sold wtih stalker.
2Asking EA to give you money for dx 10 support, i think you could expect more sales with that. Dont forget PC has recently shown it could be a powerful market.
Send a mail to the new CEO, tell him this can be a solution.
3 Organizing a humble bundle with Crytek Games. You would wait a few months to avoid making angry people who bought the game at the release.
EA has problems with sales, you have problems with sales, some pc gamers have problems with dx 11.
I think we could find a good solution, all of us.
I am not good are informatik, but you are supposed to be the wizards of informatik, so bringing out the magical script lines that would fix everything would be a way to help Crysis 3.