Board Thread:General Discussion/@comment-31283382-20150806205156/@comment-24769684-20150816183050

Ultimately, I think the only ones we're likely to see are Kyoraku's, Urahara's, Hisagi's, and maybe Shinji's. There are only six opponents left and not every character needs a Bankai; it's supposed to be a very difficult powerup which only a few can obtain.
 * Kira, Omaeda, and Rangiku haven't demonstrated that they have Bankai and they're both in situations where they likely won't do anything
 * Kenpachi has no time for Bankai training.
 * Jushiro had inhabited Mimihagi and it hasn't been indicated that he'll ever return to his body.