No regrets here, but I think I'm in the minority in terms of motivation...I only got the P85D because I didn't want to wait 3 more months for the 85D.
I have varying degrees of dissatisfaction with the issues you laid out. With the next-gen seats, I have no dissatisfaction. They weren't installed until late May, and since the bottom of my rear seats were damaged, I STILL don't have that installed, but this doesn't bother me as I look at it as getting new seats later on. I was hesitant to get the next gen seats to begin with, since I felt fine driving the normal ones, but I'm glad I did get them.
I'm mildly perturbed by "HP-gate" but that is from a truth in advertising perspective. I've been nothing but pleased with this car from a performance standpoint.
The misleading range increase is probably my biggest gripe, though it's waning as 'water under the bridge'. I don't really need long range, driving a around Boston is REALLY low mileage, and the only longer trip I go on is to NYC, which has plenty of superchargers, so it's, in practice, not really affected by this issue.
Autopilot is a the fastest growing source of dissatisfaction. While I think it's a cool feature, I only see myself it on long, highway, trips, so I didn't mind going the first few months without it. I don't travel far by car very often, but I've made a couple Boston-NYC trips this summer, and I certainly purchased my vehicle last October with the expectation that I'd have lane keeping active by now.
I couldn't care less about autonomous summoning/parking.