I'm re-posting this suggestion by @Alpha1, as we're a few years down the road and it seems a lot more people are using custom fields. I've spoke with several developers who don't want to incorporate a feature like this into their addons until it's part of the XF core (most were expecting it in 2.2). These features would be huge for increasing the usability of custom fields to customize XenForo in ways we need it to be. Hopefully it'll get some traction now.
Similar to post edit history, I would like to suggest history for custom fields. In XF2 all profile fields are custom fields. Threads will have custom fields as well.
There are various benefits for this:
- prevent data loss and destruction in case anything goes wrong
- easier to revert fields
- useful for addons
- be able to find abuse / rule breaches in previous versions of fields
- XF has a function to mass revert edits to repair mass post destruction. This should apply to custom fields as well
Additionally: If there would be Field Edit History and if there would be Field Usergroup Permissions, then this would allow for some neat new functionality. For example you could add a set of fields that multiple members can edit.