Games at 1080p are beginning to require a GTX 970 to be maxed out and not just because of the 4GB vram requirement. There are so many effects being added now.
I think the RX 480 (does 'X' stand for 10 and they have skipped 9?) will be a good option for 1440p gamers.
But it's still worth considering for those who want to play at 1080p with maxed out settings and higher frame rates - owners of a 120Hz monitor perhaps.
At 199$ it will have an appeal to a wide market for sure. But if you have the cash to spend on a GTX 1070, well I don't think the RX 480 is meant to be in direct competition with that. It is not as powerful and it costs a lot less from what we know so far.
Nvidea will respond with the GTX 1050 and GTX 1060, then it...