I managed to power trough the first season a couple weeks ago and man was it underdeveloped!
It feels like the only character the writers could somewhat connect with are the main three, all other characters just feel as props, their dialogue is so plain and impersonal, you could switch it around and there wouldn't be a difference. The main three are really the only ones that behave in ways that is unique to their personalities.
I'm personally very off-put by this Simpsons-style humor that got popular with Gravity Falls. This kind of forth wall-ish comments that characters do, that are designed to be quotable/memable but have barely anything to do with what is happening on screen. It's super disruptive, not funny (to me) and makes serious moments completely impactless.
Furthermore; what is this this show trying to be anyway? It starts of as a human girl being an apprentice to a wayward witch, then nothing happens with this plotline, then she goes to magic school, then nothing happens and we don't even see what she's learning there (or how), then some shit happens with the local government establishment, didn't seem to have much impact to the characters before the rescue mission, and I doubt it will after that.
They switch back and forth between Lily being a threat or a incompetent loser.
Which is basically my main problem with the show - it establishes shit but then doesn't explore it. This is especially grating with the concept and use of magic in this world, and Lus' relationship towards it. The fact that Lus cannot use magic in conventional ways and needs to find alternative usage of it is a cool and interesting concept, but we see almost nothing of it. Like how does she even participate in school activities? The school ended up being just a place where she meets her friends, nothing else.
Magic could be such an awesome plot device, it could be used as a extension of the characters, but it receives so little importance.
I wish Dana Terrace would have had more experience apart from Gravity Falls (dunno how long she worked on Duck Tales) because her lack in versatility really shows. She implements the same kind of story structure than GF and it doesn't work with the setting she had created.
Just as an extra point of frustration - the entire time I'm watching this show I'm silently thinking ''how cool would it be if the show was drawn in Dana's personal style''. It's such a missed opportunity

I Imagine that a change in style from the norm would have had forced the artist on the show out of their comfort zone, and the show could toy more with camera angels and proportion for comedic and/or dramatic effect. The show could adapt a lot more
show don't tell.
All in all TOW just reminded me why I stopped being interested in mainstream cartoons. They feel so dry, forced and emotionally held back.
Story lines feel strangely calculated, I have a hard time explaining it and I'm shit at writing in general, but something about modern writing in animation feels like it doesn't occur with the intent of what the character would be feeling (thus reacting), but as how the character's action can be argumented in a debate like setting.
Dunno, to me a great deal of engagement in a character comes in how much this character feels like their capable of independent thought. Like their actions are a result of their personality + situation, and their actions are unique to those.