No mana regeneration is a decision with some awkward design implications (Larian have to be much more careful how they space monsters around rest points) but I'm mostly happy about it. The one thing I would say is there should be either wands or 0 cost spells that wizards can fall back on when they are conserving their strength.
No mana regen worked in Divine Divinty pretty well (although you could get mana regen later on in the game). There were no zero cost spells or wand spells either.
OTOH your mana pool was large enough that you could cast 50+ spells without running out of mana.
