For a new or incompetent player battles are awesome. You can still be very helpful to your team even if you suck. Just turtling up with a shield will give your better teammates some cover, or just dancing around an enemy to distract them (they don't know you are useless), or having 3 or 4 enemies chasing you takes them out of the fight for a few minutes.
It seems BannerLord was built for Battle Mode (except it needs a localized voice chat). I was always against shield walls in Warband, but with upper and lower stabs and shield blocks it would make them effective but not boring. Two handers could try exploit weak spots in the shield wall or battle for the flanks. Archers could try flank for more damage but be at greater risk from Cav. And cav could fight for the flanks or try charge the ranged.
Of course such tactics would be for clan battles, where the players are a little more disciplined. But pub games would be fun too. Being a scrub sucks, but just being a part and following a group of good players is great fun, especially if you get a lucky stab in here and there.