It's a pretty trivial complaint, but I definitely find it unusual that the core "classes" even still exist. After all, what does a Gladiator have to do with a Paladin, other than using a sword-and-shield?
It's just a nod to the very first Final Fantasy and its "class change" system. You likewise didn't HAVE to do it, but there was no denying that the post-change classes were overall stronger.

By the same token, back in FF1, what did a Fighter have to do with a Knight?