From a plot standpoint it wouldn't make sense for Mihawk as he currently is to be Zoro's final fight. The WG is the ultimate adversary that needs to be defeated. Blackbeard can become that as well. Mihawk doesn't really fit with either party right now.
Symbolically, there's certainly a lot you can do with Mihawk being Zoro's endgame. If Oda makes a scenario where Mihawk is either a CD or allies himself with the WG his sword can become pretty neat symbolism. Yoru is the first black blade we see in the series and is called the world's strongest blade. Yoru also translates to "night". It'd be interesting to see the unbreakable world's strongest sword symbolically represent the WG's long night and the stranglehold it has had over the world, only for "the night" to break in the final conflict against Zoro, one of many signs signifying the dawn.
But it's all about getting there in the first place. There is some potential there for it to happen: possible connection with Imu with the red ringed eyes, one of the few people he's kinda friends with (Shanks) having CD ties, his decision ally with the WG in the first place by becoming a warlord. All depends on what Mihawks past actually is.
Plus Zoros last fight being the elder is...OK I guess, but it's hard for me to consider that dude being stronger than Mihawk when he presumably doesn't even have a black blade, a feat that Oda seems to write as a noteworthy achievement.