Celine is def a legend. If Celine isn't, then Mariah isn't, the only notable and multiplatinum album Mariah released in this past decade was The Emancipation of Mimi, she doesn't have that much on her.
Celine, like Mariah, has kind of a loopy personality/sense of humor that most people wouldn't "get." A reality TV show wouldn't help them in any way.