[alexti]

Caelum mages have another very important advantage: they can fly. Another advantage of Caelum is their cold scales.

MotW is pretty good though, don't discount halved maintenance. Plus, priest levels are more valuable then it looks. With Caelum you have to buy both mages and priests, with TC you need much less priests.

The weakness of TC is somewhat more complex that just costs. As you said S1 is one of the problems. Another one is that TC doesn't have good battle mages worth of mass production. CM are too expensive for what they do (flexibility is nice, but not at that cost). First few CM are really valuable (for searching, forging, summoning etc). But more CMs don't bring much. MotW are more cost-efficient, but most of them won't have good spells to cast.

I dislike idea of increasing Caelum costs, I'd rather took random from high seraphs, making them A3W3. They'd still have their flavour, and good cheap mages, but they'd also get very specialized, but without any randoms and only 2 paths covered it would call for specific strategies.