Right now in PvP, a spider can drain a freep of their entire power pool in about 10-15 seconds.
Without the LM power restore, this is a huge problem in group play.
If you plan to nerf the power restore (I would suggest actually buffing it) then a counter-move needs to be made in PvP. Either nerf the power drain skills creeps have or give some pvp power pots on smaller cooldowns with higher power restore features.
Otherwise, this change is a horrible, horrible idea.
And yeah - what do you do to cashout flanks without wizard's fire?