CES will probably be a good time for stuff like this. At least displays with maybe multiple TB3 inputs.
However, I'd say that there will be a transitioning phase. TB3 is not your typical interface for a Gaming PC as those GPUs don't use Thunderbolt for understandable reasons. So that leaves DisplayPort 1.3 for your 5K connection. However, a TB3-based screen will use DP 1.2 MST for its video source.
I'm not sure if there are image processors that can accept DP 1.2 MST and DP 1.3 SST sources "at the same time". Would be great for sure but that might take a bit longer.
A 5K screen with multiple inputs would be nice to have if you have multiple workstations. As for gaming, I don't see 5K as a solid option currently simply because of the power required to get decent framerates (and that's coming from someone with a past in Triple SLI setups just to drive a 3x30" setup a few years ago).
