Well, I guess I'll be able to scratch one of my hitches soon and pre-order the new 135mm... regardless of how
@neuroanatomist feels about it
(just kidding of course:
@neuroanatomist 's opinion is perfectly legit, just different from mine).
Now on the R6 mkII... I confess I've never really considered the mkI, due to the fact that one of the major reasons why I moved from 1D X -> R5 was higher resolution. So I'm not interested in a 24mp camera (same reason I did not go for the R3, although I find that one to be far more intriguing than the R6).
But I'll give my totally unsolicited and uninformed opinion on the stacked v non-stacked debate: I'd bet on a stacked sensor for 2 reasons... a) manufacturers need to rationalize on fewer sensors to reduce R&D costs and Canon has a well known history of reusing (with a sprinkle of tweaking), and b) if the R6 mkII needs to compete with the Sony A7 IV, then it'd need some headlining feature like a stacked sensor to offset the 9 gap in mp.
Obviously I may be wrong and Canon may have other ways to bridge that gap, or they may decide that they are not competing with the A7 IV at all. I also don't know what the right answer will be.
I guess we will all know soon enough
(unless all of these R6 mkII rumors turn out to be, well... just rumors
)