I definitely wouldn't call fire magic impotent in the EE.
But I'm on team classic. I prefer the less heavy handed story and the voice acting in the EE is frankly grating for the most part. The technical upgrades in the EE have a lot going for them though.
Story isn't much consideration though in MP especially since you've already played it. I'd say play the EE and then pick which one you liked better. If nothing else the DX11 version of the game engine runs MUCH better than classic, the backstab indicator is nice, and tactician mode is desirable for a replay.
