Worstgen
Cinera
Orochi appears to have given Killer the SMILE in the hopes that he would awaken powers (Killer was just unlucky). There's no reason for him to have deliberately restricted the ability of his assassin.
Cinera
The bandages were clearly there to hide his identity. Given that Oda went to some lengths to hide Kamazou's identity, I think it's plausible that the reason Killer uses the wooden scythes was to hide his identity from the reader as his mechanical scythes were very iconic for him.
Cinera
He'd had a few weeks to adapt to them, and he displayed no hindrance to his combat ability while using them (he could still effectively deploy his acrobatic combat style). Furthermore, there wasn't indication during the battle that Killer was hindered by the scythes.
Cinera
For Zoro's case at least, we've already been told that Shusui is by far his strongest sword (Shusui slashes are stronger than the other two combined), and Zoro is a Santoryu swordsman.
There has yet to be similar indication from Killer.
There has yet to be similar indication from Killer.
Cinera
All in all, I would say Kamazou ~/<= Killer is looking like the most accurate position. Kamazou probably gives Killer a upper end of high to extreme diff fight.