Okay, here's some effort since you've given me some points:>She does nto care about her royalty
I think that's what they're trying to get across, that she's not doing as good a job as she could. But her actions show she does care: she organizes events for monsters, tries for reparations with the monster population, at least claims she wants the spellbook to better serve her people.
The implications are that she is interested in ruling and has no desire to hand away the crown, but the stupid Mewmans are just stupid and prejudiced and mean :(
I would've found it more interesting if her not wanting to rule was shown through, say, she refuses the crown and Star has to take charge, or her selfishness makes things legitimately worse and Star has to step up. And while the latter is something I think they may be leading to, I don't think this lead-up is being done too well.>she cannot perform magic well without the wand
This doesn't matter, like at fucking all, when she owns the wand. It's a complete non-issue.
Once again, maybe I'd be more interested if Star still had the wand and was using it to keep her in line, but that obviously wasn't gonna happen and wouldn't make Star look too great anyway.>she is a liar
Doesn't mean much when it seems portrayed as her having legitimate reasons to lie. I want to see Eclipsa lose something from her flaws. I want her to get bitten in the ass.>she prefers monsters over mewmans because Mewmans hate her because she didnt wanna take care of them
While that is true through her favoring monsters as queen, I think as a character she suffers through not actually ACTING like that to any Mewmans she interacts with personally.
She's just so sweet and kind and caring and likable and funny and helpful and charming and nice and understanding and she's always ready to listen to you and give good advice and UGH. At least have her act more distrustful/suspicious or even cold to Mewmans so she doesn't feel like a Mary Sue.