but if I ever buy a new camera I will probably go with the Nikon D5s...
There will always be something new and better...
Yes - and a D4 or future D5 woud be a bad decision. Almost three times the price, lower resolution . . . and a ISO range nobody really needs.
The D4 is good for sports (rather fast, extremely robust) and for filming (extremely high ISO in good quaity).
But if your goal is film and less photography i´d suggest a Canon 1 DC.
I terms of shooting panoramas there´s nothing that tops a D800/810. But i prefer the D800 - because it´s AA filter.
I had the D800E first . . and i returned it for getting a D800.
Shooting panoramas you sometimes hardly can calcuate where you´re going to encounter strutures which cause moiree.
I had it several times with the D800E - i don´t like that.
Compensating moiree eats away the little bit gain in resolution which the missing AA-filter provides - which btw. is very much
dependant on your lenses - and it took me careful editing in CaptureOne Pro for dealing with the moiree. No. Production-wise it´s
not a good way.
As i heard the D810 is a bit less sensitive to moiree - but when i buy a new camera it needs to have 40+mp . . until that happens the
D800 is the optimal workhorse.