Sure he has. Maybe not with a literal smile on his face like Renpa or Ouki could do, but there have been a few instances where Shin has either cleaved through many soldiers or has equally matched characters who have like gaimou and Gyou’Un.
In fact this moment here:
Was more impressive than any formation we ever saw Renpa or Ouki break through, as this was Chou Garyuu’s “Sifting Sands” formation which was described as “the Shield of a Great Heaven” and neither Renpa nor Ouki never did anything like this to such a formation.
Eh, Ouki was covered in more scars than Houken was, Ouki just landed a few bigger hits than Houken did.
Plus Houken outright confirmed that he was stronger than Ouki anyway.
Regardless, I think Houken got noticeably stronger between Bayou and now. Ouki stated that Duke Hyou “could give him a run for his money” (taking this English statement at face value, would mean that Ouki thought of Duke Hyou as basically his equal) and Houken thrashed Duke Hyou very hard during the Coalition War.
So yeah, Shin fought a stronger Houken than Ouki did, and Shin was in worse shape than Houken was as opposed to Ouki and Houken Who were in equal shape when their fight started.
Ouki probably would’ve slayed Houken, but what Shin did vs a stronger Houken was just objectively better than what Ouki did. I still think Ouki would extreme diff him tho. Lol