My role has evolved to include some sort of "spokesperson"'s responsibilities for my technical department. For any queries, complaints, requests, etc. from other parts of the company, people have to ask me first so I can decide whether I or others can solve it directly or if I really need to escalate the problem to my superiors.
What happens sometimes (and more often in this period) is that some superiors try to push really hard, asking when a new technical feature will be released or updated, and explaining every possible reason why speeding up the schedule will be better. I usually say that I understand and it is in progress, in the development pipeline or whatever. When I know that my superiors won't change the schedule, I explain as diplomatically as possible the reason.
My fear is that more and more people within the company will associate me with being the problem person, because when it comes to things planned by my superiors, I have no way of changing their schedule.
I think this might be similar to situations any customer service representative might have found themselves in, i.e. I have no authority or ability to directly solve the problem, but must explain and calm down the complainer.
So what can I do to handle these requests without sabotaging my reputation within the company and thus my career advancement?