Between crossfire 480 and single 1070, provided, price is similar, you should go for the latter. (this coming from a user perceived as pro-AMD).
DX12 might or might NOT improve things in multi-GPU cards regard, it's too early to know for sure.
You could also go for 480, which should keep you decent 1080p and most 1440p for at least a year or so, then, later on, switch to the next gen chip.
Or if you want to go for nVidia, wait for 1060. It is unlikely to be better than 480 (as 960 is inferior to 380) but it will be close to it anyhow.
Bought 980Ti month ago, if I would be buying at this moment I'd buy 1070 gtx for sure. Less heat, newer tech, better OC, less power consumption, 980Ti performance, cheaper....
Marked red is hands down false.
I wonder, how much you paid for 980Ti month ago.
If you OC it to 1450+, you are already on 1080 levels, going for 1070 from 980Ti looks weirdo.
AMD may actually be competitive on the new process in the $200ish space.
Even this gen AMD is competitive in most areas (380 > 960, 390 > 970, 390x/Fury Nano > 980), except OC-ed 980Ti levels, where it has nothing to show.
whoeever cooked that up in their AMD head needs to be shot immediately.
They just needed a placeholder compare to competitor part of the show, imo, they are unlikely to seriously push for it.
Agree with the rest of your post.