Now what kind of training Zoro been through by the hands of Mihawk? Last time Zoro been seen fighting that giant baboon who imitated Mihawk's style or to guess the best, the giant baboon learned some of Mihawk's style.
But then, Mihawk must be taught Zoro something in swordsmanship. New World still have much up ahead. Admirals can't be that strong to wait until Zoro be at a level worthy to clash with them.
I wonder if we are overestimating Admirals. Isn't it time now for Zoro to measure his abilities and strength?