In warband archers were deadly but needed protecting save sharpshooters. Swadian Knights/Mams in open fields took near no loses. In seiges, Husks/Rhodok sargents were unstoppable. In testing the comps in bannerlord, it seems like everything is normalized, and no units comp pulls ahead a whole lot, save cavalry which mostly ends up clearing the battlefield the fastest due to speed to chase everything down. At least after troops are Tier 4+. Before 4, archers seem fairly weak.
1 crazy thing i noticed with a test save, was to siege the same city with 3 setups. 1 with all sharpshooters, 1 with mostly sargents,and 1 with all vanguards for cav units (all the L26 units for vlandian). all 3 fights with 130 troops took the city within a small variance in deaths/wounded. Maybe it was just luck.
If you take a look at stats and how the AI plays, atm I think most units are paste/copy of each other with a couple uniques unlike warband where the units all functioned different and used different weapons.
The best comp I seen so far end is simply using whatever special units in the faction you picked that go over level 30 due to weapon skill level.