The thing is, if Mihawk teaches him how to do it and that's all he needs to do, he doesn't come away looking like the better man. Like Shanks has been helpful throughout Luffy's life in a sense but hands off after the Sea King incident. Mihawk returning to face Zoro after a time span shorter than they spent together is like... dance partners more than rivals, lol
Basic people will assume this mindset and wanting it to be Shiryu means hating Mihawk. No, it means enjoying tension. That's what builds a story. Yes, he already vowed to avenge Kuina. But fighting Shiryu wouldn't mean avenging Mihawk. It just means setting his sights on a goal tougher than his original goal. This guy's a dick, sneaky as hell and was already strong enough to be a warden, which a lot of people sleep on. Beating him has to mean more than beating a guy with feelings for him in terms of the workload. Blackbeard has no real cap on how powerful he can become, so Oda can really go nuts with Shiryu being dangerous if he wants.
Basic people will assume this mindset and wanting it to be Shiryu means hating Mihawk. No, it means enjoying tension. That's what builds a story. Yes, he already vowed to avenge Kuina. But fighting Shiryu wouldn't mean avenging Mihawk. It just means setting his sights on a goal tougher than his original goal. This guy's a dick, sneaky as hell and was already strong enough to be a warden, which a lot of people sleep on. Beating him has to mean more than beating a guy with feelings for him in terms of the workload. Blackbeard has no real cap on how powerful he can become, so Oda can really go nuts with Shiryu being dangerous if he wants.