Surely a bad title for my ticket :)
Two things that could be nice
1- You can already add custom attributes but they are always visible to the requester.
Ticket attributes could be hidden or not and only visible to administrators.
This is the same for the attribute of type "user", indeed we do not necessarily want to leave the information to the requester. There can be several administrators but the requester does not necessarily have to know their names.
2- Have attributes that can only be modified by an administrator (useful for ticket status, for example)