Larian Studios Forums Divinity - Original Sin Divinity Original Sin - Help/Tips/Tricks Spell Synergy - 2 Mage Party (recommendations)

Even having a Bajillion AP, your starting AP is not that astounding until verrrrry late game.
So it is still a better idea to go (Hydro + Pyro) and (Aero + Geo).

Witch is always good either way. Elemental Affinity is amazing for Hydro, and more of a late game choice for Geo and Pyro. Never bother with Elemental Affinity for Aero.