I have to agree, they have nice stats.

Resist to lightning is so-so.

Water IMMUNITY is great.
( invokers and conjurers may delete,
especially if this certain storm giant is a maran. )

Waterbreathing is cool as well,
you don't have to worry about dispel underwater
and all those seaweeds.

Their only real "vulnirability": they have to be good.
Considering that average pk skill of goodies is lower
that one of evils... That's a balancing factor.

Should they allowed to be neutral for example,
they would receive 3 more vulnirabilities :)