Zoro's real dream is exactly the reason why ZKK is viable. Zoro's promise to Kuina was not 'beat Hawk-Eyes' but this:
Much as I love Mihawk, he is only the best swordsman of this era. By no means would defeating him carve Zoro's name into the annals of history. Slaying Kaido, the guardian deity of Wano on the other hand...
Unless of course you think Mihawk is so great that even heaven would hear of the one who defeated him...