That's the reason I propose this: no one except a few n00bs like me use this, and this is supposed to be the ace building of Rome. And no, currently it can't produce champions, and in my last patch of it there's no champions, but citizen soldiers and siege weapons. Can build in age 2 cause this is nearly useless in age 3 (I only use it to garrison my champions before I send them).
Instead of spawning champions, doing exactly the same thing in the other 11 civs (exluding ptolemies that got an early, original strategy since they win without champs), I propose to win in age 2, not rushing, but with territorial expansion (very characteristic of Rome), supreme numbers and siege firepower.