I'll be honest, the companion system is cool and all but I wish there were more options. I think it would be really cool to make certain npcs able to become your companion. Like say for example you do a series of quests for a certain npc and the choices you make in conversation with this npc (and possibly even the quests he gives) effect whether or not he becomes your companion. Similar to how in single player rpgs, there's often a character who your actions/choices in game affect whether or not they ever join your party. This way not everyone would necessarily have every companion so it feels a bit more personal.
Aslong as I get a chance to still get that companion (loosing my other perhaps depending on their alignment) by changing my lightside/darkside point ''balance''