Personally I will suggest that all those that require change of civics check to be redesigned.
Especially those that have to do city acquired checks, like state religion yields, all the corporation ones.
Capturing a city while you are changing civics on the same turn is bound to be problematic.
Those that do not require city acquire checks, like repriocity, are less problematic, but you might as well scrap those together, so that there is no turn check required at all.
Currently, every single turn, you are checking every single player whether there is a change of civics, which involves a loop through every single civics, plus comparison etc.
In short, it is a 19 player * 30(forgot how many) civics checks every single turn, regardless of whether there are any civic changes.
Which means, at least 600 checks done every turn.