Standard stuff (overuse of epithets, written accents), and I have a baseline for how poor the grammar and spelling can be before I leave.
Other than that, I don't much like the fics where Germany being Holy Rome with amnesia is just smoothed over like that, it's kind of idiosyncratic but I really don't like the way it's taken in a lot of fic- as an instant-Gerita button if they weren't together before, or as something both of them would accept without questioning either their own attraction towards each other (in Italy's case, "am I attracted to Germany or Holy Rome", and in Germany's, "am I attracted to Italy or is this residual feelings from Holy Rome") or asking a lot of people why nobody fuckin' told them anything about this. Or both.
Also, if the half of a pairing who's more the bottom in fanon is topping, making that one suddenly super-seme super-manly because there's no way anyone can top otherwise.
/ooc
Other than that, I don't much like the fics where Germany being Holy Rome with amnesia is just smoothed over like that, it's kind of idiosyncratic but I really don't like the way it's taken in a lot of fic- as an instant-Gerita button if they weren't together before, or as something both of them would accept without questioning either their own attraction towards each other (in Italy's case, "am I attracted to Germany or Holy Rome", and in Germany's, "am I attracted to Italy or is this residual feelings from Holy Rome") or asking a lot of people why nobody fuckin' told them anything about this. Or both.
Also, if the half of a pairing who's more the bottom in fanon is topping, making that one suddenly super-seme super-manly because there's no way anyone can top otherwise.