I’ve seen some services that utilize uservoice to handle requests for features, functionality, etc.
And I have seen companies have formal Request For Enhancement / Enhancement Request / etc processes (generally culminating from support cases (hopefully from good ones)).
What I don’t see, though, is a way to either limit who can submit requests (uservoice, for example, allows anyone to register and submit ideas to different groups, so far as I can tell), or focus requestors into contributing / voting-for / etc previous RFEs (the way the SE family tries to prevent duplicate questions).
Corporate RFE systems tend to be completely blind from a requestor/submitter viewpoint to see whether something similar (or identical) has already been asked for.
The wide-open option uservoice provides has its own pitfalls: finding previously-asked items is hard (unless they’re already highly voted); getting a previously-refused request reconsidered is difficult (or impossible); the interface is less than desirable.
There needs to be a consistent RFE tool made and used so that filing RFEs for a VMware product becomes more-or-less identical to filing one for WebSphere, or Chef, or AutoZone, or Amazon, etc.