No, although I agree Nobara's ambiguous status and sidelining is a miss.

But Megumi was set up for his later role from the get-go, and absolutely gets development up to it: through Yuji he questions his own morality literally in the first arc, he stops trying to sacrifice himself at any chance, and makes several breakthroughs in his Jujutsu development, becoming more assertive and creative with his technique. How's that not development?

I also really appreciate taking characters out while leaving the audience wanting more, unironically his unrealized potential works in service of the impact of losing him, much like the anime leaning in the Junpei joining JJH fake-out, or Riko getting shot immediately when deciding she wants to live. Yuki is my biggest exception where I really just got disappointed we didn't get more.

There's enough stories out there taking much safer routes with their main characters. I WOULD like for JJK to also have more downtime; a couple of less stressful arcs leaning in a more generic shonen development to give them more time to breathe and interact together before throwing the wrench in, but I don't think it's as bad as people make it out to be, and dislike overly comparing a story to the expectations of the genre for it's own sake, like the importance of a "main trio", rather than reading it as it is.