While I don't fully disagree, I do think this story was kind of getting to it's end real soon (which is ashamed), but based on the current storyline in MBML, I would rather have the sequel so we could at least have the comfort of knowing where their story went.
Think of a time-skip in anime, or the "years later.." title card of a movie: if that's how the plot moves on, then I don't mind. I'm just glad to see some of these characters again in a different story.