>Misty hasn't even appeared in full in the anime for 11 years

I watched the anime in like 1999, back when I was dependent on it appearing on some awkward TV channel, so eventually lost track and never got around to re-following when technology caught up. Why was the decision taken to start cutting original characters and coming up with new ones every time?

>Misty had no arc and nothing to add

So why not develop that, create more and solve the problem? It's not like Hermione had much of her own arc. I don't know if Misty is popular here or not but there must have been some aspect of "group of friends together through it all" they knew they were losing when they took that decision.

And that still doesn't really explain why Misty didn't turn into a peripheral character occasionally used for support/help/advice/plots rather than gone forever.