I really like some of that. I was thinking it would better if there was a throw skill/click or something so you didn't need to equip it instead of your normal weapon. Or a way to attach it to bolts to fire with your cross bow. I don't like #5, with the exception of greese+fire no other spells self damage and I don't think it would be needed if there was a cooldown on use.
Though I also like the idea of a turret/help (craft a stationary thing that throws grenades). Takes a grenade as a component, with a lengthy cooldown.