Nah, it's all good
Having companions being playable only add to the game, it doesn't subtract anything at all.
I don't think you are catching what's the issue at hand actually is.
It's not like having a companion playable as an origin story detracts from him.
It detracts from the pool of companions they can realistically implement for a game because making a companion also a "playable origin story" means making that companion several times more expensive to create, both in terms of budget and human resources.
Frankly if put in front of the choice of having, say, 16-20 *good* companions in the game and having 6-8 "playable origin" companions of the same quality I know perfectly well which option I would pick.
