It would be very useful to allow creation of releases without dates so that PMs can experiment with release buckets of features before adding release dates. This way it would not give incorrect release dates to stakeholders.
|Release time frame|
This already exists. You can create Releases in the Parking Lot area that do not have dates. Scroll to the right in the Parking Lot and use the + to add a Parking Lot release. You can also turn Releases with dates into Parking Lot releases by using the Action button when looking at a Release.