Well, if you haven't yet, you might want to take a look at my thread on stat boost spells and the possible consequences thereof... withdrawl effects and possible addiction seem to be relatively popular so far. Addiction would also be a prime candidate for cure drawbacks I'd think...
Second night back in town after a intensive week long dungeon crawl...
"Hey, man listen, I'm sorry to wake you, but.. I need one of those healing spells..."
"wha? What happened did you get in a bar fight?"
"uh, no, man, its just... I just NEED one, ya know... I think I might have some internal bleeding, maybe..."
"You look fine to me, why don't you just try to rest, and-"
"No man, you aren't LISTENING!!! I NEED THE SPELL! Just stop jerking me around and CURE ME DAMNIT!!!"
Insert traumatic "crossbow-whipping" scene and a later intervention...
"I guess I just had to hit rock bottom. I signed in to to the temples 'de-cure' program the next day...."
Kahuna Burger