A simple "yes" to requests/wishlists has indeed been a staple of their comms and I understand its vagueness, and that is why I stopped asking for new moulds long ago. It is certainly not something an individual collector can change and I respect that.
In terms of mould improvements, I do realize it is also unlikely to receive useful responses due to the complexity it involves as opposed to the its effect being a fairly minor change. Last time with the 777 though, I was lucky to have received updates on the moulded details of the wings that I suggested, in the form of diagrams. I still remember getting surprised by the level of dedication they showed to an individual collector like myself; and while perhaps it isn't something I should expect for every occasion, having received such response before certainly had my hopes up.