The problem I see is that the Vizard aren't very well developed as far as combat prowess. Jushiro and Shunsui are the 3rdf and fourth if not 2nd and 3rd most powerful captains. They were struggling against the Primera. Hitsugaya and Soifon are fairly competent and struggled against the 2nd and 3rd Espada. Sure, many of the Vizard used to be captain level, but now they've got the devilish trio, the espada, and Wonderweiss to deal with. It's a tough sale to believe they're capable of taking that.
Straw Hat is overdue for a combat appearance, so it's quite possible he may join in the Karakura fight.
As for Yami? 50% chance Kenpachi decides to go again, 30% chance Unohana my show off her stuff (but only if he's truly 0 level), 10% friends of Ichigo take him on and 10% Kisuke decides to open up a portal to Las Noches.
I'm pretty sure that the Vaizards are about as powerful as that hollow Ichigo, if not more powerful. Ofcourse, that was against the fourth espada, so no idea if that would be enough against that Wonderweiss who just took out a captain with one casual blow.
Shunsui for some reason hasn't gotten to bankai yet, I doubt he's out for the fight against that Primera.
I am still hoping Kisuke joins the fight and shows his bankai, I recall he once told Sado that he couldn't train him as his bankai was too lethal.
I did expect all the fights to get a bit dragged out more, it seemingly goes rather swiftly to be honest. (especially compared to the fighting Ichigo and co did in Las Noches)