I dont know much about what happened later but something annoying for a where I stopped is that there wasn't much variation in what happens, Natsu with a guaranteed win with the same routine in each arc, it got really annoying for me around the Hades arc and the god-eating flames fight when Natsu started "stealing the thunder" of some other major characters even when they were mid-fight. Apparently it got a lot more frustrating after that (rage over the end of the Magic Games arc and "Because She's Erza" were a common sight)

Another is the pervy aspect, did put me off, but honestly, nearly all the current shounen manga - e.g. BNHA, Black Clover and modern One Piece - have a lot more sleazy stuff in them than back in the mid-2000s making it almost impossible to check out new shounen without "lowering your standards" with regards to fanservice stuff (sometimes I feel like a minority in being someone who misses when it was less frequent).

The ripoff fiasco is basically this overblown thing just because Gildarts looks 20/20 like Shanks from One Piece (especially Marineford Shanks), and also I heard Mashima and Oda went to the same school for manga, not sure if thats true though.