Yes! This. So much this. Filoni pisses me off too. Ashoka could've meant something, but instead we have to create new levels of goofy magic universe portals that Doctor Who would've even shied away from, in order to bring her back (because, as is mentioned around here, she is Filoni's personal body pillow for some reason). All just so....we could have more Ashoka.
Rebels was a tiresome slog that went on twice as long as it should've, completely lost its way in the process, got really weird, and in the end I wished I'd never recorded and put the energy into keeping up with it. I say this all the time at home: FOR A MINUTE THERE the series looked like it could go in the direction of being a cautionary tale about turning to the dark side. Space Aladdin was a useless, shallow character, but for that brief moment where Maul was Wormtongue-ing him into going with him, we got a glimpse of how marvelous everything could've been.
We've never had a story exactly like that, but we could've seen, well, the dark side of turning to the dark side. Space Aladdin becomes Maul's personal apprentice-lite, turns against his friends, final battle ensues. It's not a Vader-level story, but a low-level everyday kid. Coulda been great.
I mean, it's not like they had a specific arc planned for him! Which became brutally apparent in the end.
/rant