What about the video specs? 120fps in HD?
Canon is very predictable overall. Even when they "shake things up" like they did with the RP, its in a very segmented way (leaving off DPAF, randomly leaving off 1080/24, having no 1080 mode for EF-S lenses, etc) to protect other products. So, in this case, the 90D will almost certainly not surpass the 5dIV or EOS-R in major ways.
So that means things we almost certainly wont find, that people would want, are
4k60
1080/120
10-bit internal
Things we might find because they arent a major issue:
no crop on 4k (because 1.6x is loosely equal to the 5dIV's 1.7x crop)
IBIS (since it'll likely exist in future EOS R models)
And things we'll almost certainly find because they've been standardized to some models:
4:2:2 10-bit HDMI output
C-Log profile option
ALL-I and IPB quality options
4k, but not DCI 4k.
Rolling shutter that's pretty bad
And it will continue to be the case that if you're looking for pure video quality, a GH5 + speedbooster will be better than a 90D. If you need a camera that is 75/25 photography, then its a tougher proposition to decide on. And I say this as someone shooting A-cam GH5, and b-cam 80D since its my primary photo camera. A 90d with useable 4k (or 6dII for that matter) would have really helped me out this summer.