I've seen that video before. Criticism is quite common regarding the small grip cramping hands. There is a good reason why Fuji developed the metal OEM bolt on grip. Palle Schultz 2:13 minutes into the video is a perfect example of how 8-12hrs of shooting can cause hand cramps. I guess like any human we can adapt
I've always found with my hands that the panasonic gh3 and 80D fit perfectly in my average sized hands. I actually prefer the 80D smaller grip over my other Canon's. I'll admit the reduced size 5dmk4 body is a nice improvement for my hands. The 5dmk3 actually has a bigger hand grip. The 5dmk2 was slightly smaller than the 5dmk4.
Everyone has a preference so I'm just vocalizing my experience....again each to their own. The cheap aluminum bolt on grip on my X-t10 is substantially more comfortable over my X-t2 even with battery booster.
My sensitivity to grip might be different since I do not tether my camera's in most cases. If I have my X-t2 on my hip with spider holster I do not use a neck strap or wrist strap. Been doing this for years and the more edgy grip a camera has the more confidence I get holding it. This liberating style of shooting can be catastrophic !!!
At this moment in time I still think the 80D is one of the nicer universal bodies Canon has ever made in the crop sensor world. Canon has nothing to even keep up with Nikon's D500 and now new D850. Remember Canon is still slugs when it comes to innovation. Nikon/sony is worlds ahead. Fuji is just starting to catch up finally with remote flash and Hss/ttl.
The more and more I think about camera gear I feel it's better to have different brands so you have more choices in gear in their strengths. That's just me......
I find using my fuji gear less challenging in exposure as it's wysiwyg also in good light majority of all photos should be spot on in sharpness with no back/front focus. This is where I reprogram myself when I shoot Canon. Different style of shooting when I use my Canon.