I'd definitely say that you are reaching a bit. But, I know that sometimes you have to reach like this. Especially in fast paced shows where the writers don't have time to spell out every character's personality in bold letters. I just never taken the time to deeply analyze her character. What do you make of the other girls' personalities on this show? Who is your favorite?
Let's start at "Osborn Academy". One of her first scenes is where she's rescued by SpiderMan from the Jackal, but she criticizes him since (in her eyes), he messes up quite a bit when trying to save her. Later on, when she meets up with Peter Parker, and knows of how he saved Horizon High from the fire, she's flattered to meet him, and doesn't chastise him when he fumbles. Later on, when SpiderMan uses a suggestion she thought of, she's a bit snotty, but does give genuine thanks to him. This also helps establish her relationship with her uncle Raymond Warren, mainly in how he saved her from falling while as the Jackal, and she is shown being courteous to him at the end of the episode.
"A Day In The Life" helps show more of their family dynamic. Even with his shady motives, you can't deny that Raymond is genuine when he talks about how smart she is.
"Party Animals" kicks things into high gear. She's obviously crushed when she finds out that her uncle is the Jackal, but we also see her gain more respect for both SpiderMan and Peter Parker. When she confronts her uncle, SpiderMan manages to swoop in and save her, and he offers his condolences. When Peter Parker comes in to console her, she reveals how her uncle inspired her to pursue science, and Peter relates by saying how his uncle helped him pursue science. She's genuinely touched and gives him a hug. This helps her establish how she's legitimately starting to respect SpiderMan while also sow the seeds on how her relationship with Peter is important.
A brief moment, but in "Sandman", while Anya and Miles try to get others to safety due to the destruction that Sandman inadvertently caused, she's the one to suggest using one of the water guns, and modify it to work here. Plus, she's slightly miffed at SpiderMan for taking her invention, but doesn't linger on it.
In "Ultimate SpiderMan" , when Miles comes in and tells them that he has spider powers, while the girls are excited, Gwen is a bit more reserved, and thinks that they should analyze the effects. While not completely on the same level (since Peter being skeptical is because he doesn't want Miles to think he can goof off as a hero since Peter isn't a slacker), it does help show they're both generally level headed.
"Halloween Moon" helps show how she's like a moral compass for others. She shows zero hesitation in wanting to keep the transformed kids safe, openly criticizes Hulk for the mindless destruction he does when trying to fight them off, and is very willing to work with SpiderMan. This altruism is further expanded in "Screwball Live", where she shows zero hesitation in helping Peter crack the code to Hammerhead's flash drive. Plus, when he remarks "I think what I was missing was you.", she flashes a small smile showing her appreciation for the sentiment. Also, they both dislike Screwball before her full heel face turn.
We see more of her dynamic with Peter in parts 1 and 4 of "Rise Of Doc Ock". In part 1, she's the most willing to put up with Otto and his ego, and is only slightly upset when Peter criticizes her before being nice to him when saying he should visit him in the hospital. Again, when you consider how "Halloween Moon" showed her as a moral compass, it works. In part 4, she's visibly crushed when she thinks SpiderMan destroyed her uncle, but quickly turns around when Peter tells her that the Jackal in prison was a fake. Plus, she's shown working effortlessly with both of them later on, or at least showing support.
This part well get a bit lengthy. The first two parts of "Spider Island" show quite a bit to her character. Because she was in the line of the explosion, she gains spider powers. While a bit shaky early on, she says: "My friend Peter Parker has a saying: 'With great power comes great responsibility.' ". If that doesn't spell out how important Peter is to her, I don't know what is. When she manages to stop the bomb and save the city, she lets her ego inflated with all the praise, and is rather condescending towards SpiderMan. In addition to being a great foil to Anya, who's nicer during heroic acts rather than real life, this also makes a great parallel to her uncle, and how they're different with powers than their normal selves. Raymond Warren presents himself as a genuinely good person, but his true colors are revealed as a vindictive monster in more ways than one. Gwen is still her altruistic self, and while she obviously has standards, is still emotionally vulnerable. Let's look back at "Party Animals" and the two Rise Of Doc Ock episodes she was in. She was crushed at how someone close to her was revealed to be a villain. Not only that, he caused mass amounts of destruction with destroying Midtown High. That would definitely traumatize a teenager. Those episodes show that, unless it's small scale or much more potentially fixable, she's traumatized by how bad things can get. Hence her cockiness makes sense since she just wants to feel better about herself due to being able to directly help more people. She's obviously softened up after the encounter with Black Widow. After being mutated and turned back to normal at the end of part 5, she's clearly a nicer person due to the support she's gotten, is not as determined to have spider powers even if she could help more .
A minor point, but she showed none of her sarcasm in part 2 of "The Hobgoblin", and was also willing to help SpiderMan and keep his secret.
So, what have we learned about Gwen here? She's a smart, altruistic girl who's emotionally vulnerable and is level headed. The trailer for the season 2 premiere also hints at her being able to help directly without powers. Though briefly, we see that she's in some kind of command center, hinting that she'll act like mission control for him.
As for your last two questions, Gwen and Anya are my favorite female characters, and the other female characters have plenty of potential to develop more.
And that's my analysis on Gwen's character. What do you think?