I agree that aesthetic wise the series took a turn for the worse after 98 but I’ve come appreciate 99, 00, & 2k2 in more recent years.After 98 I didn't spend a lot of time on KOF, at least not as much as I did 94-98 because the NESTS storyline didnt really grab my attention like the Orochi so I cant really comment on 99-03. I played them, just not as much as the previous ones.
Up to 98, I guess I'd have to say 95 is "the worst" but even then it doesn't feel right saying that because 95 is awesome.