People who bought Nikon ZR cameras seem to really love its giant screen, I hope Canon will do so with the R6V !
IBIS or not IBIS ? Some want it, some don't... In a cinema approach, there often are more cons than pros for IBIS, I think, considering the use of tripods, gimbals, steadycam, etc.
Alas, I suppose Canon would not put an IBIS firstly because of heat dissipation, wich is easier with a sensor screwed on a metal plate with dissipator, instead of a floating plate that cannot passively convey heat outside the body. If they keep IBIS, I think they'll need a fan for extreme long video shots.
But CR says there will be no fan, only vents for a passive heat circulation.
If we add the problem of body thickness when there are IBIS + vents, it's likely there will be no IBIS to keep the body thin enough. But will it be really thin ? CR doesn't clearly answer !!

However, for a video/cine camera, I don't believe Canon can (today, after the R5 story) heavily reduce the recording time at max resolution because of overheating ! So, we have 2 options : IBIS+fan or no IBIS+vents ! My 2 cents...