Instead of designing 5 classes per team I suggest consolidating the classes down to maybe 2 or 3 per team. On the pirates you could get rid of the captain class and then give his shotgun to the sharpshooter. Which would buff the sharpshooter a bit. Then the Skirm could have options of either an explosive keg or a barrel full of parrots. Like 6 parrots. As a wacky way to preserve all that work.
Another way I think I've seen pitched here already is let's say you were to get rid of the Gestir. Then perhaps the Huscarl can choose between either a 2 hand axe or a spear for his main weapon. Throwing axes or throwing spears for his ranged weapon... etc.
One thing that would not be very fun is if this game starts becoming centered around purely group pvp. Or if, when the healers get added, a team *must* have a healer to be competitive. Or it might be the case vice versa. When the classes start getting niche roles I think it would just be impossible to balance for 1v1.
Right now classes sort of feel like they have specific roles yet in every 1v1 scenario the game feels balanced and rewarding.