This is something that I harped on quite a bit back when the free-to-play model was first announced. In order to be a well-received and well-used system, the Cartel Market needs to be a supplemental system and not the focus of the game. It should compliment gameplay, provide an alternative method for unlocking certain things, but as soon as exclusive content comes to it, that does not bode well for the reception and longevity of such a system.
You've made a unique point here I think. The CM hasn't really before offered an exclusive feature. This is mildly concerning to me. If, say, pazaak(I actaully prefer sabacc) or swoop racing are considered non-game impacting features, they could potentially be implemented through the CM. Though even if they did so, it would not be enough to make me quit, I would view such a decision very negatively.
For example, I play MMOs with a decent number of people. We simply don't LotRO because it has integrated itself so tightly with it's in-game store. Content that was available in the core game at release is no longer available, even as a subscriber, because everything has been partitioned and gated by their store. So we don't bother, even though it is still my personal favourite MMO. I don't play it simply because the focus of the game is unlocking through the store rather than through the game. And as a requirement, not as an alternative.
SW:TOR is showing early signs of heading down that path.