For some reason neither Sommers nor Killingham strike as Zoro opponents. Sommers has all the makings of a Sanji opponent but Killingham has nothing like a Zoro opponent. At the very least not an arc opponent.
There are three characters with ACoC (Luffy, Zoro and Loki) and three characters who need ACoC to be defeated (Gunko, Killingham and Sommers). If Sanji has to beat Sommers right now and ACoC is the only way then are we to expect that Sanji will unlock CoC, ACoC and master it to a level above Gabans who was unable to permanently (for remainder of arc) defeat Sommers.
There is obviously some reason that Luffy, Loki and Hajrudin have stayed back with Gaban while the others have gone up.
There are three characters with ACoC (Luffy, Zoro and Loki) and three characters who need ACoC to be defeated (Gunko, Killingham and Sommers). If Sanji has to beat Sommers right now and ACoC is the only way then are we to expect that Sanji will unlock CoC, ACoC and master it to a level above Gabans who was unable to permanently (for remainder of arc) defeat Sommers.
There is obviously some reason that Luffy, Loki and Hajrudin have stayed back with Gaban while the others have gone up.