Then look at Vampire Knight..
Thirsty because I was talking about part 1 Sakura, not necessarily part 2 Sakura, but even in part two it was still the same shradde, and yes I am draggin' in Lucy because I was trying to make a point of an anime character that is used for fan service that still serves as a better purpose than Sakura.
Lucy has a goal for herself. Sakura does not.
Lucy's character is not built for the purpose of trying to please a boy. Sakura's character is.
We actually know who Lucy's parents are. We don't know anything about Sakura's family.
Congratulations, Lucy has substance and Sakura is boring, but I can't be telling that to someone who finds that to be decent character development, can I?
Caveat: I never said Sakura is a great character - I just maintain that she isn't as badly written as most of you bash her with pointless hate. Now that we are clear on that let's move on to actual reply-
Isn't half the problem here is that Fairy Tail is a character driven story? In writer's words story of Fairy Tail it was simply sitting in bars and partying with his friends, the community aspect, but is also about young people finding their calling. Characterization is a major thing going for that manga otherwise I don't see much praise for the plot or depth of the story. All guild members have to have some action because they are team in that adventure. But you forget that such character then fight the trailer made villains - with whom they are most suitable to fight and thus gain feats. But it doesn't make them as more substantial character by default. To me she strikes more like Temari if we are talking about "type" of character, even though Temari is in supporting caste only and not part of the main team.
Back to Naruto- One plus or minus depending on how you look at it - story of Naruto is not story of shinobi world and ninjas in general, not even of Konoha 11 or team 7 even but story of Naruto and his growth. Development and screen time of other characters also depends on their level of interaction with Naruto or those who are important in his life for the most part.
There is no part 1 and part 2 in manga. But if we are going by Sakura's growth as a character- she starts with a very typical random girl in team 7- pretty cliche and she instantly reminded me of Hiromi in Beyblade or other such characters. A girl which is added to the team as a non playing team mate. A sisterly/motherly character - slightly annoying and haughty towards the main character but slowly comes to know the people better and starts helping out and becomes a sort of groupie. She had every ingredient to remain in the same caste.
But then she improves- and does so despite her teacher Kakashi doing nothing to teach her anything better. He observes her being smitten over Sasuke and just let' it be. His attitude towards her protective but as a teacher he doesn't try to work on her skill much. And in middle of the chunin exams he literally exploits her weakness for Sasuke against her and drops her training altogether. He didn't even try to ask Ebisu to teach her too- which probably would have made him more check himself when dealing with Naruto.
Sakura still observes things around her and level of her team mates in general and tries to keep up as much she can - There is not much time for her to cover up initially-
In Zabuza arc there are still genins and she doesn't have hidden jubbi or sharingan to come to her aid during battle unlike the other two kids in her team. Minus those advantages she is best in her team in normal chakra control at her level and understand theories well and it's no surprise she doesn't notice the problem at first.
By the Chunin exams she was already nervous before entering it and has noticed that the other two have certain advantages over her. Kakashi entered her because she was part of the team. And funny thing is - that despite his constant hits on Sakura, Naruto is entirely self centered initially and it's Sasuke who noticed her discomfort and who gave her confidence. During chunin exams again it's Sasuke who tells Naruto to save Sakura no matter what. He was there to support her even in Zabuza arc. And Lee had challenged SAsuke over her. During chunin exams Sakura put twice her life on the line to save him despite it her being considerably weaker to the opponent ( Naruto too- the kunai and then when both guys were unconscious.). He was angry enough seeing her hair cut when he came back to life. So there was enough interaction between Sakura and him for Sakura to fall for him beyond the initial crush and Sasuke was reciprocating enough despite her his general aloofness.
But during that chunin exma break both guys had leaned some awesome tech while she was told to sit in a corner by Kakashi. And before long Itachi appeared. That lead to Kakashi and Sasuke in coma while Naruto was off with Jiraiya. Not much after leaving hospital Sasuke leaves. She did jump in between them - a suicidal attempt to stop them and if Kakashi wouldn't have intervened she would have been a goner. So she was not a silent observer even before deciding to be a medic. She just had limited means.
In terms of chapters and serialization it was a long enough time but the actual time passed was not that much. When and who would teach Sakura? And how exactly she was supposed to stop someone like Sasuke? She was clearly relatively new person in his life and his brother and family's death had been on his mind far longer and very strongly due to circumstances. Shikamaru didn't even let her come on the mission and as a last ditch attempt she asked Naruto to bring him back. She still likes Sasuke till the end but he is not her only goal in life only someone whom she still loves. She does NOT stop improving in his absence nor tries to ditch village or her own ideals for his sake.
Part of the infamous promise was to give Naruto one of the many reasons to bring him back later on, another was to lead him away from her and towards Hinata. He had already fought with Neji in her name. And after this mission proved itself a big failure and seeing Naruto's condition in hospital she asked Tsunade to train her. Result of her training as a medic and as a fighter was shown in Gara rescue arc after the time skip. But clearly her growth as a character was not static even before that.
Lucy has a goal for herself. Sakura has too- she wanted to be a shinobi. She became one. Then she decided to expertise in medicine and she became an excellent medic too. Barring Kabuto and Tsunade dew can compete with her in that field. Not bad accomplishment for a normal girl. And she achieved this without flashing her body on routine basis and she is interesting enough character to make so many arguments over her.
As for substance - not having a love interest has nothing to do with that. The whole Fairy tail manga is not known that much for "substance" let alone a character if you are trying to go for that. Probably saying, Lucy is more "fleshed out" character would be more correct.
Serving better purpose - yea if fighting tailor made fights like Nami or Lucy do and providing fan service when need be is serving the purpose then yes they do. lol
Otherwise I think Hwa Rin served in progress of the hero better than all three.