I'm pretty disappointed in Ashura. He burst into the scene with the interesting premise of a jaded warrior who's spirit was broken over the course of 20 years. Oda doesn't do nearly enough with the idea and only hand waves it with Ashura giving exposition on his time then and finally deciding to join. And since then, he's been totally bland. I can't think of one distinct character trait besides "I love Oden."
I'll wait on Denjiro. The fallout on his time with Orochi hasn't settled yet. Sasaki said he'd never forgive him, but Denjiro still spared him and educated on the Kozuki to him, as if to convert him. Then there is Orochi's forces who are indecisive about fighting the Alliance or siding with them. I don't think the Scabbards are totally out of this, and we might get some more moments with them. And since Denjiro still has some loose ends, he has the best opportunity for that.