Oda knew what you don't...Agenda aside, Sanji get the role to carry Vegapunk away that he already accomplished and not fighting Kizaru at the moment.
Put Sanji back to backing up Luffy is just wasting of time because Nami also sent Jinbe to pull up Zoro from fighting Lucci, so there's no way y'all still need fighting at this moment.
As Zoro fan I'd love to see Zoro finishing his fight with Lucci asap without knowing who's winning the fight, this arc need progress this been a year now.