I do'nt think its that powerful. especially when it comes to naval warfare. I'd never had sea dominance if it was'nt for the retraining option. The other thing is I'm with sun tsu here. Usually I never had more than 2 units at a time for retraining.

Where it can be real powerful is to throw all your depleted units in your capital of Arretium as Julii making it look poorly defended just waiting for the civil war.

Civil war breaks out ........ doh the Marian reforms have come at the same time. oh well so much for that tactic.

And as I ca'nt watch what the A.I. does it may hurt them more