Oh boy, it's been some time since I've gotten an analysis like this time to see what we've got here:
I've talked before about Starlight's roles in her village and a lot of it comes from the dialogue in the premiere by the others. Referring to her as the founder of the village makes the most sense of why her village is arranged the way it is. She founded it so obviously she would be the first to settle in. And being the founder you make a home and then branch out an build around it to make a community. Literally that is why town halls are in the center of town. But okay maybe she could've just put her house at the end of of one side, but what purpose does that serve? As the founder she wants to make the first impression of the village and by being at the end of the row of homes you'll inevitably get to meet them. Having an almost cut through path is pointless for any gathering as it allows visitors to slide through without interaction. Also on the topic on Starlight's house, it's not like she lives fancier than them either and uses some kind of power dynamic to lead the village either. She has just an ordinarily looking house as we assume the rest of them have and she's not even taking advantage of her cutie mark either and speaking of which...
Um duh, that's not good leadership, that's literally the reason the Mane 6 were called there by the map. If Starlight were a good leader then the Mane 6 would have no reason to free the villagers. The villagers thought Starlight's version of friendship was an acceptable one in spite of the sacrifice because she did have the charisma to bring the community of together. It felt real but it was based on deception as revealed by her cutie mark still being used. Of course Starlight was a hypocrite, as is the theme for most flaws behind the philosophy of a cult, but the important distinction is that while she did this to please herself it was NOT to have power over others. Starlight was a self centered leader, as in doing things in ways that she would have control of the situation in order to get the best outcome for not just her but for how others perceive her. The village was made to make her happy and feel secure in her philosophy by making others feel secure in her philosophy. There seems to be a warped consensus that Starlight is a one-pony show, and only uses others to get what she wants but doesn't really need them. As if they are her playthings and she will toss them aside when they no longer become of use to her, that the world is meant for her to control that no pony should be above her and her philosophy when the exact opposite is true; she needs them and she knows it. She needs them to reinforce her philosophy is good that it is the right way to friendship, that she is actually doing something right in her life. It doesn't matter if she had to lie a little bit because in the end the friendships they made still felt real right? That's how she sees her place in the village, in the world. And lo and behold one of the best re-enforcers for her philosophy landed right in her village. An alicorn, no a princess, with influence all over Equestria. If she could be indoctrinated into the cult then others would surely follow her lead and prove to Starlight that her methods would work for Equestria and satisfy her fragile ego and where does this come from?
Oh yes time to do some deep thinking into probably the most complex backstories in the show. Oh I don't mean it's complex because it's really deep and sympathetic and stuff. No far from it. It's complex because there was a very intended way to interpret it but the execution left far to be desired in order to understand it right making it the easiest backstory to become frustrated with. But anyway here's how I see it and in fact there's really only one part that gets me:
Always the first conclusion to jump to and inevitably the incorrect one as she flat out says what the problem is:
There seems to be a disregard for the fact that Starlight's motivation in the premiere for being against cutie mark didn't come out of nowhere. AS if her backstory is like that of a villain being like "Why did I want to blow up the capitol, oh because my friend moved away and I was lonely now and that just made me crazy enough to blow up the capitol." I'd agree if that was the logic, well there is no logic a friend moving away and mass homicide do not have a reasonable connection but Starlight's backstory has logic. A friend get's his cutie mark and in turn receiving that cutie mark causes him to leave. She cannot go with him because she doesn't have a cutie mark so she cannot leave. You said it yourself,
Sunburst therefore discovered what he truly is and can be himself out in the world but Starlight couldn't. She had no cutie mark, she had no future, she had no connection anymore to her friend. While a little over the top some of this can be attributed to a child's viewpoint on the world and cutie mark. Still cutie marks were a built up as a big thing this season as not even those that receive it truly understand the importance of it sometimes, like Troubleshoes and Diamond Tiara, but even then they do have some future right? What was Starlight's now? Could she make another friend only to have their future be different than hers? I said before Starlight is a self-centered individual with fear of the unknown. The only way to be assured of the future of others is to control it or suppress it, and that's exactly what she does. If she can prove to ponies that they don't need to listen to that mark that determines their future, they'll never have to face it, and they can stay where they are forever, and that's all she wanted. The villagers would never leave her, they'd always be her friends if they didn't have a reason to feel different, walk a different path in life like Sunburst did all those years ago.
Now like I said, this is the logic behind the backstory and my defense to why Starlight's character makes sense. What I cannot defend is the mishandling of correctly displaying that logic for the viewers to understand and not jump to the wrong conclusions like they do but that is less on Starlight's character herself and more on her execution which I won't lie and say has been flawless especially in the beginning of her reformation.
I will touch on the other points sometime later but for now, this is my defense for her time as a villain character.