I am also responding to Mray's invitation to comment here about the old troop assignment system.
I will echo what others have said and wish for a way to assign companions and specific troop types to something like an auxiliary unit.
I have always liked to keep my physician companion in reserve and out of combat.
I also enjoyed assigning Beni Zilal royal guard and Khan's Guard to a unique(ish) troop type (VIII) that was otherwise absent from my army so that I could turn command of all other units over to AI sergeants and keep those specific troops under my character's command as a retinue guard.
