Personally, while I think bronies can ask too much at times, I don't necessarily think that things like asking for darker and more mature plots is necessarily a bad thing. I don't expect anything as big or dark as, say, a Game of Thrones plot. But to expect somewhat darker plots and deeper character development is hardly asking too much. Besides, let's remember: Lauren Faust intended this for all ages to enjoy. Granted, she said little girls and their parents, but I think she pretty much meant family friendly/all ages. Besides, many Disney movies often deal with dark and deep themes including betrayal, death, etc. I've seen people argue that Disney was intended to be for families, whereas MLP is going for like 5-7 year olds, but I just can't bring myself to agree with that. Some of the writers besides Lauren Faust have said that their target demographic is between 6-12. And while Disney movies may indeed label themselves as, and be recognized as for families, they still market towards little girls arguably as much as Hasbro does. I think there are arguably just as many Disney princess fans that wear Disney princess shirts that are no older than 5-7, as there are little girls that same age that are into MLP.
Also, I think another reason fans expect it is because the comics often tend to be darker and deeper than the show. Having read arcs like The Return of Queen Chrysalis, Nightmare Rarity, Neigh Anything, Reflections, the whole Fiendship is Magic mini-series, and Siege of the Crystal Empire, they're often fairly dark and/or emotional. I don't mean like Game of Thrones dark, but dark by MLP standards, and probably on the same level of darkness and emotion as a classic Disney movie. Especially when you consider everything Celestia had to go through with Starswirl and the alternate Sombra, not even getting a chance to say goodbye. Also, think about how Luna reacted when she found out everything Celestia had done, including interacting with the alternate version of her. That's not even counting the fact that Celestia nearly sacrificed herself and had to say goodbye to Sombra for good by the very end of things. This was probably one of the saddest and most emotional stories to come from the comics or show, IMO. I also think Sombra's origin story and Siege of the Crystal Empire were very emotional too, for similar reasons. With that said, I think Siege of the Crystal Empire is very unfairly hated, but I won't go into that. Although, I do understand that the comics probably have slightly more leeway, since, even though their target audience, like the show, is young girls, comic books in general are more often read by pre-teen boys and/or adult guys. Combine that with the fact that the writers are well aware of their older audience, aka us bronies. Which isn't to say that there aren't any little girl comic book readers, but I still think they have a bit more leeway for these reasons.
I think those plots are matter of how you choose to interpret things. Especially when you consider Twilight's rather poor relationship with her old Canterlot friends, as was evident in the series premiere, as well as the fact that in Friendship is Magic part 2, Celestia reminded Twilight that what she said is she needed to make some friends. And Fluttershy said herself that he had a history of being a freeloader. Although, admittedly, he did give up too easily on most of the jobs he tried. So I think Flutter Brutter was a little bit of both.
Well, that's my two cents on this anyway.
I'm SO glad to see I'm not the only one that enjoyed Siege of the Crystal Empire. I think it gets WAY too much hate. I understand some of the gripes people have with it, and I acknowledge that it's not without its flaws, but it's far from the trainwreck most people treat it as.
Personally, while I think bronies can ask too much at times, I don't necessarily think that things like asking for darker and more mature plots is necessarily a bad thing. I don't expect anything as big or dark as, say, a Game of Thrones plot. But to expect somewhat darker plots and deeper character development is hardly asking too much. Besides, let's remember: Lauren Faust intended this for all ages to enjoy. Granted, she said little girls and their parents, but I think she pretty much meant family friendly/all ages. Besides, many Disney movies often deal with dark and deep themes including betrayal, death, etc. I've seen people argue that Disney was intended to be for families, whereas MLP is going for like 5-7 year olds, but I just can't bring myself to agree with that. Some of the writers besides Lauren Faust have said that their target demographic is between 6-12. And while Disney movies may indeed label themselves as, and be recognized as for families, they still market towards little girls arguably as much as Hasbro does. I think there are arguably just as many Disney princess fans that wear Disney princess shirts that are no older than 5-7, as there are little girls that same age that are into MLP. Also, I think another reason fans expect it is because the comics often tend to be darker and deeper than the show. Having read arcs like The Return of Queen Chrysalis, Nightmare Rarity, Neigh Anything, Reflections, the whole Fiendship is Magic mini-series, and Siege of the Crystal Empire, they're often fairly dark and/or emotional. I don't mean like Game of Thrones dark, but dark by MLP standards, and probably on the same level of darkness and emotion as a classic Disney movie. Especially when you consider everything Celestia had to go through with Starswirl and the alternate Sombra, not even getting a chance to say goodbye. Also, think about how Luna reacted when she found out everything Celestia had done, including interacting with the alternate version of her. That's not even counting the fact that Celestia nearly sacrificed herself and had to say goodbye to Sombra for good by the very end of things. This was probably one of the saddest and most emotional stories to come from the comics or show, IMO. I also think Sombra's origin story and Siege of the Crystal Empire were very emotional too, for similar reasons. With that said, I think Siege of the Crystal Empire is very unfairly hated, but I won't go into that. Although, I do understand that the comics probably have slightly more leeway, since, even though their target audience, like the show, is young girls, comic books in general are more often read by pre-teen boys and/or adult guys. Combine that with the fact that the writers are well aware of their older audience, aka us bronies. Which isn't to say that there aren't any little girl comic book readers, but I still think they have a bit more leeway for these reasons. I think those plots are matter of how you choose to interpret things. Especially when you consider Twilight's rather poor relationship with her old Canterlot friends, as was evident in the series premiere, as well as the fact that in Friendship is Magic part 2, Celestia reminded Twilight that what she said is she needed to make some friends. And Fluttershy said herself that he had a history of being a freeloader. Although, admittedly, he did give up too easily on most of the jobs he tried. So I think Flutter Brutter was a little bit of both. Well, that's my two cents on this anyway.