Thats a good example. The 1UPT is definitaly a core concept. Still, at least to me, it was easier to swallow than the civ switching mechanic.
I´m not entirely against the civ switching. Its just the way it was implemented that bugs me. My complaints regarding this is the abrupt change (abrupt in game, it of course represents a couple of hundred years wich I have no control over) from one civ to the next. I thinkt the civ switching should be slow and incremental instead. Maybe as a cause of severel events and decision over the course of say 50 turns slowly turns my Greek culture into Byzantin. Maybe also throw in crisis (wich dont have to be global).
And I don´t like that any culture can more or less change into any other culture. I thinkt they need alot more civs and let civ-switching be restrained to more historical acurat (or plausible) culture changes.