Frankly the fights that have their original mechanics built upon in gradually more interesting, restrictive, or challenging ways are the best ones. Fights that constantly go "VWOOP here's phase 4, which is actually an entirely different encounter from phase 2!" have all my hate from a game design perspective. Add phases to mix things up are one thing, but I seriously wonder why Twintania and Nael couldn't have been split into at least 2 entirely different fights.

I mean, other than to arbitrarily drive raiders crazy.