I only have my cleric (just hit level 18 with him) and find him to have a lot of the same limitations that you describe with the sorcerer: I'm continuously trying to replenish my mana when I'm soloing. I can do it, going 1-2 levels above my own, because I can HOT early, and by about level 15 there's a new healing spell that lets me completely replenish my health bar from 0, but there's a good reason why I put most of my crafting money and energy into alchemy and cooking. Fights take a good long time because I don't deal much damage.