You make five assumptions here. All of which, are very wrong.
1. That me wanting Gwen to live has anything to do with me liking her. Which is wrong. I don't particularly. Nor do I feel any real attatchment to the Peter/Gwen relationship in any version. I kinda hate "first love" relationships, and never find myself fond of the idea of first love being true-love. I also don't really like pure, good girl types, I find it annoying and fake, and despite that Emma's fabulous in her performance, and the character is written in a good way, I find the only reason for me to actually like the character is because she's played by Emma Stone, and even then, I feel Marc Webb, and the off coverage and editing stifles her performance. So, it's not really a matter of liking, I didn't want BDH Gwen to die, I didn't want the SSM Gwen to die, nor did I want Ultimate Gwen to die, although she was pretty awesome and I loved her so much, so that's not really fair. Like I said though, not a matter of like, or want. You may not understand this being in the mindset of "I want, so it should", while, for me, it's always been, it shouldn't happen, so I don't want it to, but, it's a matter of principle.
2. That Gwen, and the relationship of Peter/Gwen can only offer what's already been done, or "o they're so cute together", or even the fact that they have to end up together at all. Which is wrong. If well written, it could very well detail the trials and tribulations of being in a relationship with someone while being a superhero, and trying to find a balance. Or, it would be nice, if, for once, in this supposedly relatable story, about this supposedly relatable superhero, you, ya know, ACTUALLY SEE SOMETHING RELATABLE. People don't live in the world of metaphors, and they are HARDLY relatable. Gwen breaking up with Peter is VERY relatable, her realizing that, with good reason, this isn't something she can really do, not wanting to experience of losing someone again like she lost her father, and it can even bring about the same effect, him feeling like Gwen's break-up means that, because he can't be with Gwen that maybe in some way he shouldn't be with anyone, thinking that no one could ever possibly understand, or should experience, the danger that his life brings, and that he'll just bring them pain. If done right this could be VERY realistic, and relatable, and make both parties involved not look like bad-guys in the situation. Not to mention it has the added bonus of not making Peter look like a tool for getting with MJ, who will see Peter's pain, and want to be a true friend and help him through it, which will bring them closer together, and make Peter, in a very powerful realization, that he can have a life, and be Spider-Man, and that just because Gwen couldn't live this life, doesn't mean that someone else can't, or doesn't want to. Which would only serve to make Peter and MJ feel more right together.
3. That Gwen being a strong and powerful woman automatically equals: Being written like Mary-Jane! Which, guess what, is wrong. A similar action does not make one or the other at all alike. That's like saying all strong woman are alike. Which is very false. Gwen is being written in a different way in these films, stronger, as a non-damsel in distress type of character.
4. That Gwen's death holds any sort of relevance to anyone outside of Spider-Man comic-fans. Which is, again, wrong. People will be sad, maybe angry, but at the end of the day, ya know what they'll all say? "Seen it before." Because they have. Because it's been done to death. Because by this point in superhero films the only thing new, sadly, is the happy ending. It's rare comic films. Now THAT would be truly shocking.
And finally 5. That death and pain is more powerful than a character living. Wrong. Character death is a cop-out, it's a cheap, half-assed way for a writer to instill "power" into something when the truth is, they don't have the skills to give a truly poweful end. TDKR was one the most powerful superhero films I've ever seen, and would you look at that? Nobody died to give it.