Kaido, BM didn't do shit before facing Luffy
All they had is portrayal of being yonkous - status to hype them.
Dragon has no individual feat to back him up as well yet he enjoys the big hype as well.
So why making a fuss about Mihawk?
To be fair, yonkou are at the top of the food chain. We actually saw some hype from them, let's not lie to each other. But yeah, Oda put in place the lame rule of 3 powers (shichibukai, yonkou, marines) that consists in avoiding fights and keeping balance.
Dragon should need feats because Sabo is over-shadowing him now.
Mihawk will get at least one fight, because he's not fighting Zoro in the endgame. Someone will kill him and Cross Guild will shit its pants, Crocodile will tell Buggy to stfu and keep acting like a yonkou.