I don't know, the Shisui idea sounds too arbitrary to me although we can't rule it out. I would count it as poor story telling to just pull out Shisui from out of the blue. I mean what possiblebenefit could he add. He can't save Sasuke with any known jutsu he possess.
Out of the known candidates who might be bare footed, close enough, and possessing of potentially life saving/game changing jutsu, Kabuto is still the best choice.
It does seem that After the Tobi = Obito thing (debacle?), we did lose a lot of fans and debaters. It's almost as if people threw up their hands and said WTF?
Actually, thinking about it, I am not sure if it wasn't simply a decline of Mangashare itself. Even the Mods disappeared, and the site was being heavily spammed. It took a Whole Lot of appealing before safeguards we implemented against spammers. Even now, clickable functions don't work.