Cabaji, Nyaban Brothers & Hatchan were not Opponents who earned Zoro's Respect, He also fought them Nerfed
Ohm Fight was also more of a Challenge (Iron Trial) than a Duel & He won using Flying Slashes which he learned in Previous Fight already
Lucci being a Villain was not planned from Start (Actually even Robin wasn't among Original SHs Draft), so Kaku was added too
Hyouzou couldn't even kill Zoro's Boredom. Pica relied on Hiding more than facing Zoro straight on, so nothing worthy of Respect here either
As for Zombie Ryuma, not only Zoro fought with Two-Swords, but the guy was a Zombie & Zoro said let's pretend this Fight didn't happen
So when you really think about it, aside from Mihawk
Mr. 1 is Only Rival of Zoro whom Oda created
He is Worldwide Famous, an Assassin & Former Bounty Hunter just like Zoro, his DF basically makes him Infinite Sword-Style User, Zoro defeated him with Extreme Difficulty & He is only one among Zoro's Opponents who Lost cuz He didn't know Zoro could Hurt him (All the others were careful when dealing with Zoro, but Mr. 1's Defeat came as a Surprise for him, meaning if they had a Re-Match with Mr. 1 knowing he can be Hurt, it would have been even Tougher Fight) ... etc
This might be Controversial, but i believe Mr. 1 was Stronger than Pre-Enies Lobby Zoro & also Stronger than Kaku
And Post-TS He should be even More Powerful
After all, he is "Sole" Right-Hand Man of a Shadow Yonko with 1.9B
Unlike other Zoro's Opponents who have others sharing their Rank or Higher
So Yes, imo Zoro Respects Mr. 1 The Most after Mihawk