Are they OP? Yes. Being able to smite five people at once and kill them all is OP. But when used to taste I can take it. They are supposed to be a threat after all.
Eh, just use the Lighting a little bit less. I realize sometimes it slips, but it can really get annoying. Use it like, in meaningful situations only. If you listened to me, mobs should be used much more than the lightning . Also, get some rp fights in there! Thats always fun.