Zoro already got the best feats when 4 others WG were (including Kidd) there so no need for Zoro to prove more, he is just an underling right
... The only one to prove more is Kidd because Luffy's rival, right ?
At least Zoro got his 1 vs 1 and gonna beat the RH of Kaido, for kidd well it will never happen ... not even Big Mom gonna fall in 2 vs 1.