@yorosenpai
I do think Oda is gonna show King's face and there is a lot of teasing regarding his backstory as a Lunerian and the Celestial Dragons. Yeah I can't wait to see their extended fight animated, and Toei has been putting the talent and budget for Wano.
Everyone seems to be getting power ups in the climax from Luffy mastering advanced COA with Conqueror, Sanji unlocking his genetic potential, and Law and Kid using awakening.
Its safe to assume that Zoro is gonna level up soon as well. Turning Enma black makes the most sense since its been teased since Dressrosa. So far Oda has been very cryptic on how to do it. Onimaru stated that Shusui was forged into a black blade through many battles. Hitetsu teased that Wado Ichimonji is a key to taming Enma because they were both created by Kozaburo Shimotsuki.
However, I do wonder how Oda is finally gonna show Zoro's long awaited flashback...