The primaries would be cool, however they are not really built for multiplayer. Brute is just northstar with the vortex shield and acolyte pods. Expedition also has vortex shield and acolyte pods as well as electric smoke which is earned in multiplayer. Ion already uses vortex shield as well. If they could maybe give the two titans their own abilities in multiplayer, that would be awesome.
What if Expedition and Brute were variations of Ion and Northstar. If you roll over Ion or Northstar then it would show a tab next to it that if you go over the titan loadout it would allow the choice of Brute with going over Northstar and Expedition with going over Ion.