I hope they have left it for Mystic of light specialisation atleast.
Actually, shouldn't this Fountain of spirit be more useful in LATER stages, when you are supposed to have more spells (buffs&curses) to cast than in the beginning (so you will need batter mana regeneration). Isolde has a point too, because some battles are exhausting and you don't stand great chances untill it is replenished. However, I am more in favour of the idea that in order to need faster spirit regeneration, one player should also have where to use-up the spirit first.