That's probably not unbalancing at all, but if you're feeling a little uneasy, house rule it to ask for some requirements like the reserve feats, for instance: as long as a sorcerer can cast a 3rd or higher level spell, he can use his cantrips all day long.
Alternatively, you could say that his unlimited cantrips work on the lowest spellcaster level possible (say CL 1 for 0-level spells). So if you want a more lasting
light (Duration: 10 min./level) you should spend a cantrip slot as normal.
I don't know if that could work or not, but I think I'll do that on my games. I mean, I want my sorcerers to be 'magical' but not entirely

And I hate managing resources like ammunition or wand charges, so giving them 30 cantrips a day just won't do it for me.

Edit: as for the Cure Minor Wounds, you could have a divine variant of the feat by house ruling that particular orison
not to heal 1hp, but instead to get dying characters into "stable" condition. Just a thought...