Prior the rooftop feats, i would say zoro.
But it seems like zoro has gotten too strong too quickly in wano.
Even at his current powerscaling right now, which can range from somewhere between Marco and Fuji,
he should be able to take on Shiryu right now.
I guess what I am saying is zoro vs. shiryu can happen, but it won't be an extreme diff fight for zoro EOS.
It would be more of a fair fight to have sanji near EOS vs shiryu in terms of power level, but the issue is we can't find someone in BB crew near/higher than zoro's level besides BB himself.
Yeah, this.
After his unbelievable performance in Roof Piece, I just find it difficult how ultimate invisibility can threaten Zoro more than top tier fights. Hence, if Aokiji is really a part of BB's crew now, even if only to maintain a ruse, I'd rather see Zoro vs Aokiji, tbh.
Besides, Sanji vs Shiryu is not without its merits:
1. I do not see Sanji ever defeating a top tier solo, so I think the fight against BB pirates will be Sanji's first and maybe last 1-on-1 fight in the series. Even if I am not a fan of his, I acknowledge his relevancy to the SHs pre-TS and I would hate for his last solo fight to be against goofy looking Vasco instead of a cool looking villain like Shiryu.
2. Soloing Shiryu who is likely a YC1 makes it official for Sanji to be YC1 level. That is to say, I believe anyone hoping for Sanji to solo King and/or Queen this arc is in for an upset.
3. Sanji has personal history with the invisibility fruit even back when he was still with Germa. Facing it now that he is also an invisible man brings his story full circle.
4. Just like Wano provides a subversion with Zoro fighting the main opponent, Sanji vs Shiryu provides another subversion in the form of Sanji fighting a swordsman and not fighting a gag character.