It's plausible, but if she felt complete with Gambit, she wouldn't even consider the cure, would she?
At least one of the primary X-Men must be tempted directly by the cure, otherwise... well the whole plotline is useless. There'd be no bearing, no interest for the audience whatsoever.
Angel, I suppose worked for that purpose, a lead character facing that exact problem, not sure of himself, dealing with pressure, overcoming those fears... finally trusting in who he is.
But then his arc falls apart, when he simply ends up at the mansion and nothing more. No invitations to join the team, no effort made to speak up for himself, no reasoning for him to want to retain his mutation. With the X-Men, his gifts could be used for good, for others. There's no real explanation why he would rather live the rest of his life, a "freak".
If his character development were to truly have an impact on the audience, he needed more screentime, that's for sure.