I think bandit units should get some sort of visual marker or icon in the party screen (f.e. a small red dagger in the right top corner of their image) so it would be easier to identify them at just one glance. I find my self searching through my prisoners for some time, just to check if I have enough bandits for the laborer in the mines quest, would be way easier if they were marked. Also as more mods are incoming with custom troop trees, it would help in these situations, to know if these units are considered bandits by the game.