Starco earlier, in S3 to remove TomStar bullshit or limit it to a few episodes before being unceremoniously dumped like Kelco. Let Marco become her most trusted advisor and confident as they explore the wider universe beyond Earth. It never impacted his role in S1 and S2 for him to both care for their collective well being and as a sanity check against some of Star's misconceptions about the world around her (just as she would occasionally do for the weirdness that ended up around Marco}
The rise of "Star the Revolutionary" to build up the rebel princess bit. She doesn't have to be all posh and perfect, but she shouldn't be allowed to just bail from her responsibilities with no consequences and hand it off to Eclipsa. She eventually should come to the realization that to make her policies and idea ideals a reality, she *needs* the power that comes with position, and so matures to face her problems, but to do so in her own way. Or if she does hand it off, come to the realization of just how little her voice and policies are heard in the face of a monarch with a plan of their own.
Solaria, Mina, MHC, Shastacan, Meteora, Eclipsa and Globgor are *all* grey villains/protagonist. They each have done something wrong or morally questionable and those actions get put before Star to make judgement calls on. I don't mind if it still comes out that she sides with the monsters over all, but having these Star come to realize the world isn't so clear cut and to struggle with those decisions of who's right and who's wrong layering over her misadventures with Marco in the climatic lead ups to the various season finale.