I like this idea. To the extent this could be done in a way that is safe/constructive for the person/group who voted no as well as the people who proposed the IIP, this could be very valuable feedback. Even if it’s not a systematic poll, it would be helpful if “no” voters provided feedback in the forum.
Transparent, objective feedback can help make forward progress when there are proposals that can be fixed (thinking of the Beta/Rari strategy vote, which resulted in a revised IIP). There are bound to be irreconcilable differences also, but it would be good for the “no” votes to give some indication as to why without fear of backlash.