I've loved the summoner, but I'm real sick of being squishy. I'm thinking of going the opposite direction, and building a char designed to get hit.
I'm thinking tempest shield, molten shield, reckoning, vengeance, heavy resistances, melee attackers take damage, conductivity and/or flammability with blasphemy support etc.
Good for packs, but perhaps challenging for bosses. I'm thinking, as I'll be standing still a lot, maybe some channeling. Start off with lightning tendrils and see where the mood takes me :)