Having dismissed 5DSR due to A7RII's killer specs and better dynamic range last summer, I never looked back... until now thanks to your [now seemingly retracted] announcement to ditch the A7RII that got me thinking differently. I have been mulling about my camera gear roadmap and I think I hit a eureka moment over the weekend.
I have two completely different needs for my professional practice: one architectural and interiors, and another birthdays and events. I have been leaning towards expanding Sony setup, especially since their 24-70 G Master announcement. It would make the A7RII the prime and 5DIII as the secondary for both events as well as architectural shooting. However, it meant that I would end up with redundant 24-70 lenses because of the EF24-70 II that I already own and I would not give that lens up so readily - one could use EF on a Sony but not FE on a Canon. Also, in my latest architectural assignment, the A7RII + TS-E17 setup created some really horrendous internal reflections that was a real pain to deal with in the PP.
That's when your decision to go with the 5DSR prompted me to look into it once again - the price has gone down since its release thanks to tepid demand, and it is now available on Canon's refurb site. I've re-read some in-depth reviews and downloaded RAW files taken by 5DSR to compare with those I've taken with A7RII. There is some indescribable allure to the images taken with 5DSR that I do not see with A7RII - it could be color rendition, or contrast, or a combination of both but there's a sense that 5DSR images capture the quality of atmosphere that no camera of mine could. It's quite true that .ARW file has more latitude thanks to its greater dynamic range than .CR2. Then again, I realized that the process I use in Lightroom and Photoshop to adjust the exposure, especially in the shadows is pretty much similar whether I do it from a single file or from using multiple files.
Instead of another 24-70, I could get 5DSR and go with 5DIII (primary) + A7RII for events (matched with 24-70L II and 16-35IS L and/or FE55, respectively) and 5DSR (primary) + A7RII for architecture. It would mean I'd be spending approx $1K more but I'm planning on selling FE90Macro for now (and eventually reacquire Canon's 100L macro). 90 Macro is a great lens but I can't get used to focus by wire especially at close range and the fact that Sony still does not supply adapter ring with their macro lights to fit this particular lens (sold separately through convoluted supply channel) is making me go back to Canon. It also makes sense since I already own Canon's macro ring light which I jury-rigged to FE90 - something I do not have to do for 100L.
A7RII remains as a capable all-rounder, which is what this camera is all about - not necessarily jack of all trades master of none, but more an overachieving eager beaver. If I needed to travel light, this with FE55 and FE24-240 (dog of a lens compared to others but ultimate travel companion that did so well on my trips taken in 2015) would be a perfect setup and also very capable as a daily shooter.
Good to have you stick around. If you are serious about selling the 35L II, let me know what price you are thinking. I have a friend who is lusting after a copy and I've been telling him to wait until it appears on Canon refurb site to save some $. However, it'll probably be another few months until first refurb copies would appear, given it took first refurb offerings of 100-400L II to appear about 10 months since its announcement in November 2014 (35L II, iirc, was August 2015).
I like your plans; makes total sense to me. Obviously, if I got as far as posting my a7R II for sale it should speak volumes of my enthusiasm for the 5DS R. It is simply way better than the reviews would suggest.
Color, however, is actually THE reason I couldn't bring myself to sell the a7R II. I love the color from the 5DS R as well, but it is very different. The 5DS R color feels the more "realistic" or "natural" to me. But, the a7R II color has a dreamy hyper-real, almost illustration-like artistic quality to it. And I am simply nuts about!
But, back to your ideas, yeah absolutely: get yourself a 5DS R. It is fantastic; it is THE ideal body for TS-E shooting. 









