More than one owner
Option to have more than one owner for the tickets.
Based on your comment, would something like the ability to “subscribe” to a ticket be sufficient? Subscribing would allow users to receive notifications regarding the tickets they are subscribed to.
I do think more to allow multiple owners would help in many cases we would have in my business
No you should be able to assign to more people
Yes! it would be fine.
In my personal situation, it would be useful because in my department I share some tickets with a colleage, and if I'm on vacations or in an external client, my colleague would receive ticket's notifications or so.
But is not so important to make a large structural change, so, never mind.