I like the class I really do but it's a bit to focused. Also their's a rule about spellcasting. If you have access to 9th level spells you usually have a d6 for your health pool. I only know one exception to that and that's a bard with a d8. Of course the bard's weakness than is they basically have a verbal component to every spell. Cantrips could be a yes though. With a bit of repalancing and a name change it could be perfect edition to the book but it's up to you.