They often feel like annoying plot devices more than characters with personalities. It's not the kid's fault, they just become a focal point for issues with the writing more broadly.

> In stuff like drama its like the kid characters are ripped into for being 'boring' And I can't figure out why.

In this case, because unless you're retooling the show to really deep dive on the kid, they're by nature going to be a simpler, stupider character than their adult equivalent.