I would love to see the feature that expands what can be changed about a deployment. Specifically the date/time. Right now deployments are created at that point in time. My use case has us pinning a deployment to stackify sometime after the deploy, so the ability to set the day/time is crucial.
This would also allow us to pin other useful milestones that aren't exactly deployments... but are related to performance. Like server config or hardware updates, network changes, etc.