I have been hoping to have this added for some years but haven't seen much traffic on it.
One of the issues we have is that when adding a node you have a bunch of fields to update. This allows for a lot of typo's, bad information, etc.
What I would love to see is that where there is already information for that field in the database then have it populate a drop down for existing data or allow you to add at that point.
Something like this:
If the user selects one of the fields than it will populate that box on the form otherwise it will allow them to input data. Once the node is saved then that value would then show in the dropdown box for that field.
Likewise it would be great to be able to lock some fields down to not allow users to add changes.
Best feature request ever! Everybody needs this enhancement.