Interesting post, and I think those things could be true, but also bend the narrative a little more, after all it is a show, and they wanted a happy ending.
My main critique would be in regards to Steve. I think it's less of "he let one get away," and more, "not everyone is going to share the same feelings in a relationship." What you're saying; there was something within Steve's power that would have allowed him to "make" Nancy stay with him, regardless of her feelings. It was pretty apparent in the show, that their "love" was mismatched as soon as Jonathan appears. It was on Nancy, and Nancy's free will to choose who she wanted to be with. One could argue it was the "actions" of Steve that pushed Nancy away, and maybe if he didn't make those choices, they would still be together, but that just isn't reasonable. If Nancy "loved" him, she would have seen past those simple mistakes, and the decision would still ultimately be up to her.
Another comment I would like to make. I full expected Bob to die. Why? Because he wasn't flawed. In a show where every character's arch is created on a flaw, a non flawed character is not going to last. It's simple writing and story telling. Bob simply had to die for the show to move forward.
Good write-up, and I am waiting for Season 3 as well.