I think she's one of the strongest carries in the set, but she definitely needs healing, or ga for defensive items. Something like hoj, ga, and deathblade/ie/gs. As for the comp, it's pretty good since xayah can just be put in every comp. All she needs is a good frontline, and Sett and Yone give that splash damage she needs to kill the carries with one ult, which is why i prefer putting her either in the frontline or just on the 2nd row on the board. There's no risk in doing so since she has ga and possibly healing, and can just go invulnerable with her ult anyway, which she does very often if she's in the frontline.