The Susano had a great amp section, no doubt. But if one needed/wants a powerful amp, there are plenty of powerful amps from a variety of firms that can be had, ranging from Emo/Outlaw to Wyred4Sound (for class D) to Mc's/Bryston etc. That said, I've seen plenty of dead "high end" pieces, and plenty of "future proof" high dollar pieces, end up in the busted/broken sections of flea bay, so high price doesn't automatically correlate with higher build quality.
In the end, the question is moot for most AVR's in the price range you are discussing. While nothing is perfect, solid state electronics are fairly robust, and many mass produced items will last well past their features/compatibility will remain relevant.
As for SQ, I think room correction is going to be one of the most differentiable items on that list. Several good programs exist, Audyssey MultEQ XT32, Anthem's ARC, and Mc's Room Perfect for example. The aforementioned Marantz (and Denon AVR that the 8801 is based on) provide XT32. Anthems more boutique nature may appeal to you, and the D2 is available with ARC, and of course the Mc w/Room Perfect.
The D2 may be a nice spot for you. "High End" design, boutique level panache, and widely acclaimed as a very good sounding prepro.
As for me, I've played with higher end pre-pro's, and flagship AVR's. I'll admit, at the time I felt I noticed a difference, and maybe I did, but I wouldn't put my money on the line in a blind test. Currently I am greatly enjoying my Denon AVR, using its onboard amps, and I don't miss my old Aragon 8008, or Proceed Amp 5. Well maybe a little, but its mainly because I thought they were cool and fun to look at.
With that in mind, I do understand the desire to own "the best" and if that's what you want, go to town. Just don't convince yourself that there is much, if any, difference in sound quality between different well made components. Moreover, well made starts at a much lower price than some think, and a $2-$2.5k receiver is probably well above that threshold.