My problem w/ Zoro vs. Lucci is that it logically shouldn't do much for Zoro as a fighter.
Zoro still has a long way to go before he reaches Mihawk's level.
Lucci would have to be not just arguably stronger than King, but outright and obviously stronger than him to push Zoro's growth.
There's just such a huge disparity between who Mihawk and Rayleigh are (as in, the benchmarks for EoS Zoro) and who Zoro is right now. Or at least, that's how it seems based on Zoro's track record of opponents and his prestige.
The thing is, is King wasn't really a "fighter". He had durability, speed, and power, but he didn't believe in styles, or anything like that. He just used any means necessary to win a fight. He's the typical shonen "Naturally gifted but doesn't train or take fights seriously" character. Think Berserker from Kenichi, or even Frieza from DBZ.
Lucci not only has a fighting style, but he's a master of it. His speed is on another level, and who knows what Oda can do durability wise with mixing Armament Haki, and Tekkai together. In my opinion, Lucci is what King could be, if King took fighting serious.
There is huge potential here for a real good fight. Lucci is one of Odas favs. He's a former major antagonist. If Oda is putting Lucci against Zoro, it's for a reason. He's never going to give Zoro a downgrade, or someone on par, to one of Zoro's previous opponents. If Lucci is fighting Zoro seriously this arc, then he's going to be an upgrade to King in every aspect.