I'm all for leveling everything, however I think I would like the game much more if the leveling curve was more much much higher, I honestly believe that taking less than a month to cap one jobs is way too fast, and I would like it if going from 50 to 60 would take just as long as getting from 1 to 50 and so on.

As for the identity crisis, I'd like a global customization system (not per job, but for the character as a whole)

Merit system maybe? you could go ahead and cap all of your healing options and be a great healer, but end up being "Average" on all your other jobs.

You can be anything the situation needs but you can only master one or two roles.