The easiest way to get a contribution, advice or feedback is to present something that’s 90% done.
If you ask too early in the process, if you’re hoping for conceptual insights, you’ll probably be disappointed.
Human nature pushes the inexperienced feedback giver to wait until you’re almost done and then to offer feedback on little things. Tactics, not strategy. Colors, not shapes.
Which means that you either need to teach your team to be strategic professionals, able to give big advice early…
Or create enough room in your (private) internal schedule for redoing the work after someone has ‘tweaked a few things.’