To be honest, in a non-competetive game, I couldn't give two figs about "balance".
It's not like using Leech would spoil someone else's enjoyment, and you don't have to use it if you don't like it.
On my first playthrough, I didn't take it at all, and that wasn't because I thought it was "OP" or "imba". It just didn't fit with the way I wanted to play.