I think that the barbarian factions should be able to train enmass every turn if their population allows for it but only historically accurate troops.The Gauls for instance did not have any trained troops per se............rather they had tough experienced warriors.........not soldiers.I would allow all factions to do this also but for the Romans i would limit this to militia troops.I haven't really thought this through yet and i know i have just made an unfair generalization of the Gallic units but i do feel that CA have given abilities to some nations troops that they never had.