I mean we are basically returning to the original approval, minus some of the mega-units on the uppermost floors. The units up there are unlikely to be small, "ryanair" type units still.. just not 2-4,000 mansions in the sky. I imagine they are dividing them up into more manageable ~1,000sf 2-bed units.
Ultimately even at 86 floors this will be the taller than any other building in the City. It may be a bit disappointing to lose the top 5 floors, but it's not like the building turns to crap because of it.
Tridel also does absolutely excellent interior finishes and construction quality, despite it's reputation for exterior design direction and it's preference for Kirkor.. Luckily in this case, the exterior design direction is already "locked in" and is not up to Tridel to change. They will deliver their signature, high quality interior design I'm sure for end purchasers here.
If I was a purchaser I would be pretty happy that the project ended up in Tridel's hands.
As to why they aren't pursuing 91 storeys - as far as I know, Mizrahi got the ZBA approved for the change, but never amended the Site Plan before losing control of the project. For whatever reason, I guess Tridel / Skygrid did not care to pursue the site plan modifications required.