The Wizard of Kanto
Sometimes I wonder if Mallow would've been better off as a recurring character than main cast...They tended to get the scraps in terms of character growth and involvement though. The biggest development Mallow got was the Shaymin/mother stuff, which was pretty underplayed (and probably would have been better left to finish in this series, especially with the Gen 4 remake promotions).
She could've still been an honorary member of Ash-tachii. Shoot, SM had a record breaking number of those anyway!
Heck, compared to ALL the Eevees main characters have gotten!I'd like if Sandy got something, it kinda got the short end compared to Primarina in SM.
Which is downright bizarre since she was supposed to help promote the Let's Go games. It wasn't just bad writing, it was bad cross promotion!
(though one could say that about much of PM2019... )