Although I like the Romans and playing custom battles with Imperial units, I agree with the opinions showed here.
Anyway, before removing a unit I would always think "have I completely filled any slot?", then if I need to add some units and I have no more space I will remove unnecessary ones.

However, the nasty thing in this is that I know some Italian fanboys who would get mad even by only hearing of this idea (for instance I did read also opinions of a modder who "dislikes" EB that would cast the worst deadly curses in the world to EB authors if he would notice that the holy-sacred-untouchable-mighty-superior-ubermenschlich-omg-i'm cumming-onlyreasonforallowingagameinthishistoricaltimetoexist-dreamy-ahweehmahweh Imperial legions have been removed), so I'm already imaging the flame wars...