Yeah my Triarii never really get a look in - only there to cover a retreat if necessarry. I definately agree about rorarii - they have a nice range and can pack a decent punch in melee. I use them behind the triarii though, then deploy to the flanks if needed.

Essentially my battles consist of a Hastati charge, they fight until they break, then a principes charge supported by rorarii to the flanks. Then the remnants of the hastati come back to help out. I do sometimes flank with cavalry but if the enemy has cav too, I just charge mine at theirs and let them pursue them to the edge of the map. I feel it to be more authentic like that. They can come back once that's done to chase routers and help finish off the tough nuts. Doing it like this I get defeated sometimes which in my opinion is a bonus.