Consistency sells but is really hard to ensure in time bounded series of narrow discussions with changing participants. But this must not discount the value of the preceding often frustrating search for understanding the requirements and prototyping. Throwing away the prototype while all the lessons are still in the head can yield great design.
In feedback solicitation situations with multiple stakeholders, it's important to attach cost to suggestions. Consulted without being responsible is always a dangerous offering.
Not in the sense of "This is how long that will take me" (because who cares about someone else's time?), but in "Of the 3 things you requested, which 1 is your must-have?"
Often this is approximated via design/dev team pushback, but it's easier just to be explicit about it: i.e. everyone gets X change request tokens.
