I played LA Atlantis in a recent SP game, and I loved my mages.
For the early game, my supercooled heavy infantry dominated the battlefield. I always brought along at least one Angakok and a posse of Tungaliks, but they were mainly there to watch the infantry fight & die. However, I quickly learned that Frighten spam is shockingly effective against indies (as Nikelaos mentioned), so all of those Angakoks and Tungaliks started working for a living.
But then I researched Alteration 6....
New script: Frozen Heart *5, Cast Spells. I added a few more Tungaliks (recruitable at any fortress!) to each army, and the bad guys started dying more quickly. This spell was particularly effective against the heavy cavalry and knights that were so annoying. My infantry could breathe a little easier now.
And then I researched Evocation 5....
Another new script (for Angakoks only): Falling Frost *5, Cast Spells. Angakoks with a random pick in Air magic had the first Falling Frost replaced with Aim. Woohoo! More bad guys died before they could ever reach my infantry, and my troops rarely suffered any casualties worse than the occasional "social disease" from fraternizing with the locals.
And then I researched Evocation 7....
Forging Time! Each Tungalik paused to forge a Water Bracelet, which now made them Water 2 mages. Another new script: Ice Strike *5, Cast Spells. I also added a handful more Tungaliks to each army. At this point, the bad guys died before my infantry could even engage them. By the time my troops started to swing their icy weapons, the battle was already a rout.
Battle magic rocks. It's a little harder to use than the venerable "build heavy infantry and hit people with it" strategy, but it can be exceedingly effective. And I didn't even do anything very fancy! Just pick a decent spell, spam it all over the battlefield, and watch the carnage.
