Remind me again why Sanji fans wanted King and not Queen? It's not as if King has looked amazingly strong either lol.
It's too early for Sanji to be YC1 level anyway.
Glad you asked.
1. Fishman Island was the first real showcase of the SH's new goods from their 2 years training. The thing highlighted for Sanji was his ability to use Skywalk, having even a chapter named for this (chapter 635). It is mentioned as the ability from CP9 by Luffy and Robin, giving it a really cool "unique" vibe to Sanji as fighting style goes.
2. During his fight against Judge, when Judge starts doing his "Garuda" fight style thing, Sanji makes a comment how aerial combat is his forte. Yet another highlight for this particular skill of his.
BUt the thing is, since he didn't have any "official" (not counting clashes with Vergo, Doffy, Raisin or Oven, etc), he didn't actually have an opportunity to showcase this ability of his against a similar opponent. King COULD have been this opponent. King most likely is member of a flying race.
This next segment is completely theorycrafting.
Despite Queen knowing Judge, we don't actually know their relationship, nor do we know much about King's race. Maybe he was experimented on just like Kaido. Maybe his wildfire is somehow an experiment and might have some parallel with Sanji's DJ. Sanji vs King COULD still take advantage of Queen's mention about Judge. There were cool possibilities.
That's why >>>I<<< wanted it. Can't speak for others, though.
edit.
Oh yeah, and the aesthetics of the fight would look freaking amazing.