I have a couple enhancements that I think would be great for the new expansion pack coming out.
-New Jobs:
Necromancer: Would be kinda neat, like a BLM/SMN. Would be an advanced job of course. Plus, all those damned undead could be used to our advantage finally!
Trapper: Could kinda be used as a puller. The trapper uses a trap (obviously) to ensnare mobs. eventually, the mob could break free, and then come after him/her.
-I would like to see the cost of chocobos drop somewhat, or at least be a bit more steady... Not saying this for myself, but for those low level people to whom 800 gil is a lot of money.
-I would like to see a couple more race specific mobs (Orcs, yagudo, Quadav) come in. And, make it so that they are not such a pain to exp off of. I do not want to make it easier, I just miss the days when you could fight mobs that were a bit more interesting.
-Do NOT up the level cap. This would throw everything askew, in my opinion. otherwise, you could have a pt of DD without any need of mages, except to MB. (Imagine, a pt of /NIN sub ><)
I can't think of anything else atm, but if I think up any more, I'll be sure to post them!