There is a slightly beardy trick you can use with them if you're heavily outnumbered but with better troops who can hold for a time. For example you can put the Roman meat grinder into action and slaughter a whole load of barbars. Without the capture point you'd get overwhelmed eventually, but let the enemy take it and you can slaughter a load of them then lose the battle before they have time to really damage you. Smack them with reinforcements and mercenaries next turn.