I definitely think Brutes should come back, but im pretty sure they have had just about enough of the Sangheli, so i think teaming up is out...the Elites kinda took a bunch of brutes as slaves after the events of 3.
On another note, i think brutes should act like they did in reach, but berserk like they did in 2, they were scary as hell. also, even though bungie didnt like it, i thought making them huge bullet sponges was what made them fun.