>>54723777As a TMfag myself, Nasu has irreversibly damaged and perhaps even ruined his setting thanks to FGO. The flanderization and dilution FGO has brought about is impossible to fully describe.
Nowadays, at least for me, TM has become one of those like what I like and pretend the rest doesn't exist.
The thing is that rules being broken is not a problem per-se, FSN had rules being broken all the time, but there as was a proper reason, but narrative and lore-wise. There was meaning behind those rules being broken. And frequently too it was not that rule was broken but the a thing the characters thought it was was actually not that way at all. They were working on incomplete or vague or outright wrong information. And there was build-up between such moments, when they're established and then subverted.
Nowadays a rule gets set to be broken right afterwards just for the sake of it because "it's cool" and nothing more. And it happens every five minutes. Zero meaning behind them.
Either way, a crossover is a crossover. Handling how two different settings systems will work and mesh with one another is part of the whole shebang. It just works.