One thing that would be extremely useful is to be able to dictate how many people from each role should be reserved in a group instance.
For example.
in an 80 person instance.
2 People with Role A.
5 People with Role B.
10 People with Role C.
63 People without any of those roles.
This would allow for better control of events that are run in VRChat instances.
Additionally, these options should be able to edited at any time. It would be extremely helpful useful.
Currently, what groups end up doing is create a private instance. Then in that private instance they drop a portal to a Groups+ instance and pray that everyone gets in. If someone crashes or something they have to go back into the queue (with priority which definitely helps), but it becomes a problem still.
Dynamic group instance role limits would be extremely beneficial to the Group Instance experience.