I really like the new user story map feature! Something that would make it even better for me would be to remove the functionality where it automatically creates master features and features for everything added to the user story map.
Early in the ideation/definition process many of these ideas are essentially just notes (i.e. post-its) and may end up unused or combined later into something else entirely. As it works now, it creates a trail of orphaned features in the parking lot that have to be then manually cleaned up later - and which are not distinguishable from other items in the parking lot.
Instead, I would like to promote things in the user story map to features/MF's when I'm ready to put them in the backlog. It could also create the records automatically if they are put into a release.