I suspect the API doesn't give access to switching items from vault to bag (and back again) or somebody would have done this already, but thought I'd throw it out there:

The ability to save your current bags' items as a named setting file, and reload it would be amazing.

You choose the Bag Settings plugin (or whatever) and it allows you to click Save, type in a name (say, Crafting). Then you switch your items out with stuff in your vault and save that with a name (say, Combat).

In the future, go to a Vault, then choose Bag Settings, pick Reload and choose one of the saved Bag sets to automatically switch the items currently in your bags with those in the vault. This would be incredibly helpful for those who constantly find themselves switching items in and out of their bags for certain tasks.