I agree with Tuidjy. Some sort of immunity or resistance to death spells ala an Amulet of Hold Life would be nice. Or how about a magic item that makes life draining attacks backfire! That'd be neat, I think.
Failing that, however, some sort of saving throw for the Drain Life spell and similar stuff would be good. But the issue of whether or not the Water school should have better spells doesn't really come into it.