Most of your list is there for mirrorless (not the optical viewfinder of course), just not
all mirrorless. Let's go down eh list:
I use my Sony a9ii and have yet to swap batteries when I'm out shooting (I have the grip with two batteries).
No overheating problems for most mirrorless - it's more a video problem than a stills issue.
The a9ii has the speed and AF for action, as does the R5 it seems. The a9ii beats all my Nikons save the D6 where I think it's a tie, depending on the subject.
I think the body durability thing is overblown. I'm tough on my cameras, as is my wife on hers, and the Sony and Nikons have held up just fine.
The LCD in all directions is something I've been screaming for too!
The Z6 handles high ISO with the best of the DSLRs and is only very slightly behind the D5/6. The Z7 is on par with the R5 and the a9ii is close to - but not quite - at D5 level.
Yes - the shutter should close when the lens is off.
8K is coming, not too many DSLRs are doing it either.
Z6/7 go ya covered on focus stacking
Dual cards are coming soon to the Z series (in the Z5 already) and are already in some other brands.
In short, we're close. I'm hoping Nikon gets their Z series up to par with Sony and Canon BUT goes for a bit larger body.
As a side note, I have a couple old film SLRs floating around and we all complain about the "tiny" mirrorless cameras, but you'd be surprised how similar they are in size to the film cameras. In fact, my old Pentax ME Super is noticeably smaller than my Z7. Still, I'm with you on wanting a larger camera body.
