I'd say Cyclops doesn't trust Gambit. And I don't even think that's remotely far-fetched. Yes, even after the events of Gambit's Nation X short.
And battlefield-generals don't count on people they don't trust. I mean, there's no surprise that Alpha Team consisted of, for the most part, some of the best, longest-running, and sure-footed X-Men.
As for the thing about him becoming Death, it's good for two reasons: Hellbound #1 couldn't really spend the time allowing Gambit to go through an emo-whining session before turning into Death; and it's much more interesting if Yost, as an author, explores for Gambit, as a character, a willingness to turn into Death rather than fighting against it and whining.
Oh, and the magical third: it'll look really awesome when the next issue focuses back on the team to see Death-Gambit kicking evil-demon-like-things' butts.