I don't really get your comment... but exactly how many of your companions had side missions in which you could actually participate instead of watching the screen black out while they went off to solo it? Most of them are pretty one dimensional too.
In any case, it would be super interesting if he were a new type of companion that doesn't exist yet from a skills/gameplay perspective. We have the ranged tank, the ranged dps, melee tank, melee dps, and healer archetypes. If he added new archetype for some new gameplay he'd be interesting.
However, right now I can't see BioWare doing that at all, because they will once again fall back on their story pillar, while completely ignoring the ones that make or break a game.
"Films are great. I love me a good movie... [but] why spend so much effort trying to make your game exactly like a movie when you could be making a great game instead." - Extra Credits