Its hardly a grind when doing a leveling rou with like 12hrs rested exp and food. You get nearly 3 levels worth of exp with that and in conjunction with deep dungeons and bozja it's pretty easy to get to 90 in just a few days if you dedicate said days to it and maybe also utilize your wonderous tails.
That said I don't see Square making you start at a level lower than 80 now that sage/reaper exist.
