That's totally fine - but people need to also be aware that if something is really a must then they have to be willing to spend adequate time and resources on getting it done, instead of assuming whatever resources they have on hand will be sufficient.
It's amazing the things that stop being a "must have" as soon as they have to spend more money.
It's a never ending struggle to get people to create this ordered priority. I always tell my developers to say
"if you do not give this an ordered priority, I will resolve items as I see fit. Should we need to stop for one reason or another, there is no guarantee of which have been resolved".
Often times that is okay. I also tell them to always take the ones they're most uncertain about first. Better to front load hard problems and uncertainties.
It's amazing the things that stop being a "must have" as soon as they have to spend more money.