What I think is we don't give the scabbards the benefit of the doubt here:
-Inu/Neko fought with Jack for days pretty much on their own. What they lacked was Sulong to help them win.
-Asura striked Jack and broke his weapons in one attack.
-Asura and Inu fought pretty equally as a result
-Denjiro almost seems like he's the biggest monster of them all.
We truly have no idea where Kiku, Kawamatsu, and Raizo stand but I can see them being "slightly" weaker. Kin'emon is weird. He fought evenly with Brook through "feeling" alone (probably observation Haki) and only a torso, but he hasn't TRULY shown off the extent of his capability. He was impressive at PH, but did not fight at DR the entire time pretty much, save for getting kicked by Doflamingo while trying to save Law. I'd assume Kanjuro is around the same strength. Then you have Izo returning this arc.
All in all, I expect some of these people to have major fights in Kaido's forces, and possibly Big Mom's. Don't expect the Strawhat's to monopolize the upper echelon fights. Hell, we have Supernova Captains (and Killer) that also need exposure.