250HP recovery per shot is rediculous and not comparable to a Waltz at all. Waltz costs 50% TP to use. That's about 5 attack rounds depending in your Dual Wield reduction and Store TP. That'll probably take around 15 seconds if you have a good haste setup and dont stop to cast any spells or use any JAs in the mean time. IT also then uses up that 50% TP.

A thief uses an xbow with either 216 delay (Ziska's) or something similar up to 288 delay. In that same time frame, a thief with said Xbow can make at least two shots. That would recover 500HP for free. Not only that, it would also make you do over 500 damage to the mob in two shots. It would also give you TP. That is completely overpowered.