First off, this is the second time you have told me I am wasting my money. That is a subjective basis that I don't like you making assumptions on how I choose to spend my money. I had no problems with Skyrim using 2x 660s, fwiw and that game came out in 2011 under directx 9. Also, you are taking an isolated incident of one game and using that as inductive reasoning to mean that all games have poor SLI/crossfire and that is just not true. Maybe Nvidia is just better at SLI than AMD is at crossfire.
This does not explain why you do not want directx 12 to be implemented for ME:A. So let me just ask this: Why don't you want ME:A to be a directx 12 game?
I misspoke and got the games confused. You are correct that DA:2 was the first game to implement DX11. And yet, we see that game implementing both DX9 and DX11 and I see no reason why ME:A can't do the same with DX12.
I'm not specifically referring to you at all. I'm speaking generally of anyone who invests in Crossfire/SLI. I have personal experience as I used to run Crossfire mode. I know how much of a scam it is by Nvidia and AMD just to make more money off of people buying two GPUs. I actually listed three games that had terrible Crossfire/SLI support, and there are many more. If I upset you, I apologize, but I'm merely addressing the reality of the feature and why it's unlikely to have any substantial improvement anytime at soon. You can spend your money however you'd like. That's your right. Just remember, you assume the risk. If Crossfire/SLI is either not featured in MEA or is completely broken, don't say I didn't warn you.
If MEA is a DX12 game, then that means it will not support DX11. The reason you saw most games supporting DX9, DX10, and DX11 is because all three API worked on the same operation system. DX12 only works on Windows 10. DX12, in reality, is just a more efficient DX11 and nothing more. However, the cost of making the jump would be forcing all PC gamers to have to upgrade to the latest Windows OS, which is a drawback. There is literally no benefit to MEA being a DX12 game because it has been designed for DX11 and is not likely to take advantage any of the features you hope it will. The only DX12 games that I'm even aware of are Fable: Legends and Quantum Break. They only work with Windows 10 and do not offer DX11 support.
Again, I already explained DX9/10/11 all are compatible on the same operating systems. DX12 is not. As the person above stated, and I have already told you, no developer makes their game with SLI/Crossfire support in mind. It's at most a tacked on feature at the end of development but it is in no ways optimized nor is it usually better. In fact, Crossfire actually ended up killing one of my GPUs because it was being over-taxed while the other one was idle, when both are supposed to work in unison to maintain the load. There are just too many glitches, bugs, and not enough support. Again, and I will say it for the last time, SLI/Crossfire will continue to be a waste of money until developers actually start making their games with the feature in mind from the start. Considering most gamers aren't willing to shell out $300+ for two high-end GPUs, that's unlikely to happen.