After saying to myself that I'm fine with my D810, 24-120, and 50/85, this past weekend pushed me back into thinking that I need a mirrorless system again. Went up to Newport and Boston with my wife and my 2 yr old with the 810 and 24-120 mounted packed in my Mindshift bag and my 50/85 as well. Literally took 10-15 shots at the beach in Newport and maybe 25-40 shots all throughout Boston. Had it slug over my shoulder in the Boston children's Museum with the 85 and must've hit my kid in the head at least 4 times chasing her around. My neck and shoulder feel a little sore, and that's with a comfortable bag and strap. Also handing the camera to my wife to take pictures is a lesson in frustration, since i would hear 'how come I can't see the picture on the back' to 'why won't it record videos' to 'why is this so heavy'. Prior when I shot mirrorless I did enjoy the lazy mans approach of using the rear screen at times and just capturing quick video clips. Ever since I went back to a dslr, I've taken maybe 4-5 videos because of having to flip in and out of live view. One thing I do like is the dual card slots which makes transferring pictures to my iPad super easy since I shoot JPEG to one card, and the fact of no shutter lag. I don't need high fps or a deep buffer, but taking pictures I often like to fire off 5-8 shots in quick succession to make sure I have a keeper, on some mirrorless that's not possible due to shutter lag (if that's the right word for it).
But the a7r2 fits all I'm looking for, small size, ibis, 4k now, high mp count, and if it can give me improved high ISO over my 810, then having a 1.8 prime instead of a 1.4 won't be an issue. I could see getting a 24-70 f/4 (I know this lens gets mixed reviews, but center sharpness is all I need) combined with say a 28/55/85 prime setup would take care of 95% of my shooting (I don't shoot Uwa and I'm not a wildlife/sports shooter). Just a 24-100 or so range and taking pictures of vacations and family. I'm in for a preorder at the least.