Oden's reaction to Roger vs WB

[SSJ2]

I don't think Oden was aware of Haoshoku coating considering his shock of WB/Roger's clash. Kaido also makes it apparent that the Scabbards were using the same Haki as Oden when they used Busoshoku level 2. Oden was a Yonko level fighter so his Busoshoku would've been strong enough to seriously wound Kaido.

 

[Future Warrior]

I don't think Oden was aware of Haoshoku coating considering his shock of WB/Roger's clash. Kaido also makes it apparent that the Scabbards were using the same Haki as Oden when they used Busoshoku level 2. Oden was a Yonko level fighter so his Busoshoku would've been strong enough to seriously wound Kaido.

I say this because it's noted that while Advanced CoA can hurt Kaido, it can't seriously damage him (leave a permanent scar). The only attacks that do this were seen from Oden and Zoro, and potentially Luffy right now. Luffy says in 1010 that his Internal Destruction Haki was still too shoddy against Kaido. Kaido says the 9 Scabbards attacks were still too shoddy as well.

It's noted Oden got several times stronger after coming back from his adventures.

 

[SSJ2]

Oden >/> Luffy tho. Oden was stronger than Kaido without needing to transform. Luffy can't even seriously damage him while using lv 3 Busoshoku with Gear 4. Luffy might be on his level with Haoshoku coating but not with Busoshoku.