Great idea! It would be cool if the guilds, or your personal quarters, allow you to enter an instance and practice combos, spells, and what not on your "dummy/punching bag". Make it a little diverse though by creating dummy dodo targets to beat up on, or dummy sheep, pterocs, etc. in a silly anime~ish looking form for players to purchase and add in their homes/training grounds.

Also, if you undergo personal training and pull off certain combos once a day on your dummy/punching bag you can earn some EXP to boost your character along by yet another means.