Restrict moving deals between stages
HubSpot users should be able to be restricted when moving deals between stages. Let's say you have a Sales Pipeline with stages like "Qualified Prospect", "1st Meeting", "2nd Meeting", "Proposal Given". You shouldn't be able to move a deal from Qualified prospect to 2nd meeting as there must have been a 1st meeting between.
Why is this good?
As HubSpot's deal funnel analytics works the same way it would be more accurate and this way sales people would be incentivized to update their own deals more frequently. JIRA has a similar option although it's for a different purpose, it would fit how HubSpot's pipelines work.
How to create this option?
Admin users will want every kind of restrictions, not just the one where you can only put a deal to the next or previous deal stage. As a user experience on where to add this to HubSpot I would suggest adding this option to the Deal Settings page (where you are able to edit deals and create automation for them).
I would change the "Delete" button to "Actions" and add this functionality as a possible action to choose which deal stage the deal can move to from its current deal stage.