[Twan]

You don't need slave matrixes to cast in round one in a communion, just one crystal matrix for the master, and him to be after his slaves (but of course to efficiently enslave, he probably need penetration gear).

And defender can protect all his mages and troops against rain of stones for 3 or 4 gems (army of gold or fog warriors), he don't have to make armors for each.

Then I agree SCs/thugs are the only thing usable to take a province against teams of mages able to cast endgame spells (no need of an army of mages, as explained above 10-12 are sufficient to cast all the spells in the example). But considering the defender can use some SCs too, and has no problem to have his normal troops surviving first round, you really need a thug *army*.