By the way... @Logiko, what is your opinion about Yonko vs Admiral? Are Admirals top tiers or are they glorified YC1+ characters?
Yonko, Admiral, Warlords and YC1 are not homogeneous entities in term of power.
For YC1, I don't have enough elements to say that Zoro is superior to Marco for example. Simply because Marco was able to tank 1 YC1 and 1 YC2 at the same time and Zoro had difficulty with 1 YC1. So I'd place Marco over all YC 1 right now including Zoro and Shiryu and Katakuri at the exception of Rayleigh that I would put with Kizaru.
Concerning the Warlords, I would put Doffy under Zoro since Zoro went against Kaido and slashed him, Kuma under Doffy, Law more or less at the same place as Marco or maybe just above and Mihawk largely on top.
For this same reason I don't think Admirals are equal. Fujitora and Ryokugyu seem to be the weakest. I'd say they are Orbiting around the place of Zoro and Shiryu right now. Kuzan and Kizaru on the other hand seems to be stronger and more durable so I would put them just above Marco. Akainu is clearly the strongest so he is on top around the same level as Mihawk (I can't really separate them right now)
Yonko are not equal either. I think I could place Akainu and Big Mom pretty much on the same level with an advantage for Akainu. But this is just speculation. I think Kaido is clearly the strongest of them all so I can't put Shanks on top. For me Shanks is around the same level as Mihawk but on top. Maybe stronger than Akainu. (I would place Prime Garp just around the same level as Big Mom)
Now, concerning Luffy and Black Beard its tricky. I don't see Black Beard as stronger than Shanks or Big Mom. For me this is a character that will grow in power toward the end of the story. As for Luffy, I could see him beat Shanks. So I'd say that Luffy is superior to Black Beard in term of power. But if there was a mtch up between the two, BB would be on top simply because of his neutralization ability.
Also I forgot to place Imu and the Gorosei. It feels like the Gorosai are not really "real". I've seen an interesting idea being that they are an extention of Imu's power.
So I will not place them, but I will place Imu... on top of everybody else.
So it would be something like that:
Most Warlords
Kuma
Doffy
Zoro, Shiryu, Fujitora, Ryokugyu, King, Katakuri
Marco
Kuzan, Kizaru, Rayleigh
Black Beard, Big Mom, Prime Garp
Akainu, Mihawk
Shanks, Luffy
Kaido
Imu