I dunno how I feel about PUs being Europe-only, honestly.
Feels kind of crummy, even with marriages being enabled cross-faith outside of Europe.
It vexes me greatly, mostly because of how junky PUs are in the first place.
However, if you can also diplo-vassal between all non-Christian faiths, I'll take it as a valid trade-off and mostly leave the Euros to their little luck box.