I think the main aging issues were the digital control in FFVII (a problem that's been extended to FFIX now what the fuck SE) and battle pacing along with some navigation foibles (well, and perhaps typical JRPG stuff that was merely tolerated by those who didn't normally like them?) But those were kind of issues then anyway, I remember kind of getting burnt out playing FFIX largely because of the slow battles, which makes it kind of awkward to have to choose between the fast forward of the port and the analog controls of the original.
Ugh, seriously, I would've considered the PS4 version if it had analog control put in, at least on a good sale, but that, and a music issue that wasn't on PC, and the audacity to charge $20 when it's a $10 PS Classic? That just makes me angrier that Sony didn't bother to get BC with the Classic lines in favor of doing HD/trophy updates to PS2 games that have kept the library at a pathetic size and doing nothing at all with PS1 games. I half wonder if it's to let SE do this sort of shit and keep us dipping in again for FF. Which might work if the effort wasn't so shoddy.