So as predicted X1 game cases appear to be G2 sized thus steelbooks for X1 games should be G2 as well
Granted I don't care much for the X1 thus far but who knows? May still get it if things change
Anyways why I'm pretty damn sure it's G2:
MS released cover art for Quantum Break today
They've released previous cover art for X1 but not from this direct view before
Hence the ratio between sides on this image is roughly 1.29 (cropped to just the game case of course)
The ratio of sides on a G1 case is 1.41 whereas it's 1.256 on a G2 Case
Safe to assume there was some error when I calculated the ratio of sides on the quantum break case but it still must be a G2 case
Basically all Xbox One game cases/steelbooks will be G2
I think I can hear kian swearing from here