I have a public roadmap, where people request new features all the time (https://trello.com/b/5i4VvOW8). All of people's features are in there, but some might indeed never happen.
When someone asks or requests, my response is: "Right now I'm working on higher priority things, but some day I might get to your request". It satisfies them all the time, since they understand I'm still improving it, just not their thing.
When I was a consultant with better manners than I have now, this was the right response to the constant stream of scope increasing requests on fixed time or budget projects.
“That’s a great idea! I’m gonna write it down here as something for V2.”
When someone asks or requests, my response is: "Right now I'm working on higher priority things, but some day I might get to your request". It satisfies them all the time, since they understand I'm still improving it, just not their thing.