Then I think that what your getting is what you'd expect from a 970, remember its not much more then a mid end GPU and that AC:Unity is spectacularly unoptimized, to the extent that even the consoles it was made for are struggling to deal with it, PC isn't any better. If you getting 45-60 FPS then i'd say your lucky from what I've heard. I don't really see a problem with what you've linked, given the specs of a 970.
Also, you say as long as textures and details are at max, but there is no max. E.G. Skyrim is now 3 years old, yet as mine currently stands, no game will even come close to its graphics for at least another 3, very likely more. Even Shadows of Mordor with hi res DLC doesn't come close. If like you say, your not so bothered about anti-aliasing and you can run Unity at max with anti-aliasing at 45-60 fps then i fail to see an issue, if you absolutely must have a minimum of 60 FPS then drop the anti-alising down a notch. I think your expecting too much from a casual gamer level reference card. For this reason when the 900 series hit the shelves i saved my money, knowing that the TI version would be out soon, at 8GB vram on a single card it will make a mockery of the performance of the reference models. It will likely be the first, single card that can run a game such as skyrim at its current full, graphical potential, at least at 1920x1080, going up to 3840 x 2160 would without a doubt necessitate a second card.
You stated in your first post that people say the 970 is overkill for gaming, but gaming encompasses so much that this a terrible statement to make. If a game that is 3 years old can make the 970 billow more smoke then frames then it cant be considered overkill. It may be overkill for something low res and tacky, like pong, or AC:unity, but for real gaming, it doesn't even come close. Its like GPU benchmarkers saying X card is best because it can run Y game at 1080p at Z FPS. 1080p is meaningless. Sorry to go off on a bit of a rant, but living my life around console gamers has made this a very frustrating topic for me so my apologies if i come off at all hostile, it is not intended.