Something I never liked about the anime is making all the protagonists 10 to match Ash's age. Now of course Ash being 10 in Kanto was fine, but as we got into Hoenn and beyond, it really felt like Ash and his companions were teenagers.
Case in point when we have underage sibling characters on the cast like Max and Bonnie, the other main characters look like teenagers in comparison. Same when we have filler characters like little kids in filler episodes, the first pic is a good example, May looks double their age when she's probably only like 2 years older in canon.
I honestly think making May, Dawn, Serena, etc. all 10 year olds were a mistake. Even Mallow was de-aged from her teenage counterpart. And the issue is the animators seem to ignore this and draw the characters like teenagers anyway.
by Moist_Speaker1842