You don't really need to draw the water hag, though. Lacerate is a thing on its own, in the current meta. With it, or water hag in the deck, caranthir becomes a 20 power play. He's not garbage by any means.
Anyway, lacerate is only particularly good in the current meta. I don't think water hag is too good at all, IMO, she's just a very strong card in a meta that has lots of tokens or swarm units.
In any case, I wouldn't be too opposed to giving her venom instead of lacerate. She'd lose potential value, but gain consistency in attaining max value. Not sure if that would make her weaker overall, though. Change the meta and suddenly lacerate isn't as much of a thing, and now she kills 4 strength units instead of 3.