Also... if Bumblebee somehow (and I mean this purely hypothetical) wasn't planned from the start and came about after Volume 5 as they allege, well, it fits like a damn fine glove.
After all, some elements of a story come about even when you're finalizing an absolute final draft. Like... has nobody heard about the story of Neo being introduced into Volume 2 just before the White Fang Rally was posted online? Imagine how different Volume Nine might've been without Neo.
If Bumblebee was a Neo type situation, they already laid the groundwork with Blake and Yang's friendship. Yang pleading Blake to believe she didn't maim Mercury. Yang charging in to stop Adam from hurting Blake and losing an arm. Yang very much being upset over Blake leaving and opening up to Weiss about it.
Even if they were meant to be initially "just good friends," that still lent itself as good set up for a romance to bloom. i've often found myself finalizing a story and seeing two characters hit it off in my eyes, convincing me that there's something more worth exploring.
That it wasn't there from the beginning doesn't make it inherently bad or worse.
Hell, most Manga is written by the seat of an author's pants. Even those with a solid road map of a narrative will often go, "Oh wait... what if... I added in this or that." Inspiration strikes anytime and anywhere.
Sorry to go off like that but the fact is that the creative process is a lot more complicated than how the RWDE likes to think it.
