VH/M. You can handle it.

I think that a lower setting of H/M would be justifyable for some smaller factions, but certainly not the Romans. Italy itself has amazing economic potential and you have an unparalelled choice of where to expand.

The biggest annoyances in my old Roman campaign were the continuous assaults of the Sweboz from the north. I solved this by conquering the two cities in the Alps between us, made them Type IV client kingdoms and used native troops (lots of slingers in particular) to repel the occasional siege. It was quite managable.