Probably more games as demanding as shadow of mordor could come out, but shadow of mordor used an abnormal amount of vram.
I might get a Titan X, but I will after all wait until the end of June, when Nvidia and AMD release their new GPUs, then I'll make my pick.
Honestly, 6 gb vram should be enough for 1440p. Then there is the possibility that DirectX 12 could combine vram.
I think that two 980Ti's will blow one Titan X out of the water, at a lesser cost.