You are not an asshole for asking for what you asked for. He's the one asking for change and or infringing upon you. You made a proposal let him accept or counter. Being "neighborly" has little to do with this transaction. A developer's intent when they go in is primarily to make a profit. So, his motive, most likely, has little to do with being a good neighbor and more about selling the house. If i were him i wouldn't want to look at your ugly fence and might want some privacy. You know that so you are leveraging it. I don't have a problem with that.
If the request had come from an actual neighbor who had been there some time, then I may feel differently about your approach being asshole-ish. I know it would bother me, every time i looked at my backyard, to see a new wooden fence on one side and old ass chain link on the other sides.