No, the fact is, that Rooks would beat about any combo of enemies, because there rock throw does AoE stun, not to mention it only takes one or two hits to desemate an enemy, which can be done while they are stunned. The Rooks have so much health that the damage that it requires to beat them, coupled with health potions, make them there nigh near impossible to take down.
The rook has a good 1v1 stun, but against multiple opponents who aren't total fools, it isn't an AoE. It's on a line, and that means it's predictable. Also, if you are quick enough, you have a prayer of dodging it until you get close enough to use your own stuns. I know how much the rooks can do, but the enemy has to be stunned or it's a resoundingly mediocre heavy ability. The damage other demis can put out is amazing too. A high level torchbearer chaining all their fire in the proper order after uncorking some ice (ice storm, fire storm, fire ball, closing fire nova, fire circle, fire storm again) can easily bring a pair of rooks (all AoE except for one) to the brink of death while its buddy keeps them stunned, and its regular attack isn't exactly weak. Did I mention its buddy can chain ice storms into the rooks as well? The torchbearer is devastating on offense, and that chain can easily kill a torchbearer or regulus if he doesn't get stunned and the enemy doesn't run.