Well, if I were to choose, I'd rather see Akira & Sae losing. It might not mean they would be out of the story. Them losing to Hitsugi might be exactly what they both need in order to reconsider what they really want and how to achieve their goal. So far, Akira seems to be aiming at the top only to get her father's approval or something. But if she really manage to win the duel, so what ? Losing here might help her see that she has worth on her own and what her father think doesn't matter that much.
Though, as I mentioned in some earlier post of mine, I would kind of love to see Hitsugi rampaging her way back up from the bottom, toying with the lower ranks gleefully for a revenge match. XD But well, her staying at the top would be best in my opinion...
As for KuroxAyana, can't say I really ship them. It's fun from a comedic standpoint, but the idea of them getting actually serious would feel kind of weird. AyanaxYukari does make a bit more sense to me. But what I'd really enjoy is JunjunxSigma ! <3