I don't own one, so this is purely an observation from your pic with a big white connected, can you still get your fingers round the grip, between the grip and the lens? Doesn't look like there is room, but I know it could just be the angle. I have large hands so if there is no gap it would not work for me.
I have medium hands and there is still room, so I don't think it will be an issue.
I've been playing about with my daughter's 1100D recently, using it in RAW for the first time, because I'm going to get a small body for when I don't want to lug the larger stuff around. I was considering the M, but now think I am almost certainly going to get a 100D instead because I really like the tiny dSLR form.
However for myself the size of the camera body must match the lens, so I would never buy something so small to use a 70-200 on a regular basis.
I agree, I would never use the 70-200/2.8 it looks and feels ridiculous, however the 70-300L now that's different ball game, I've taken this combo as it appears in the pic to many outdoor events and it is now my fav combo