Soldato
Don't you think the work AMD have had with Mantle will have them having a better understanding and implementation regarding DX12?. This is a question, not a strange way of me telling you something .
I don't know
We will just have to wait but right now unless you game on 4k or are changing real soon You may aswell save your money and wait for DX12 to be out and games to be ready for it then decide how to spend your money on a future solution.
Buying for future proofing right now seems pretty risky.