It would be very useful to have the ability to edit the Field Maps form for any web map that has been shared to you. At the moment, in AGOL, you can only see My Maps. The workaround is to create a Shared Update group, which lets other users make changes to the form but then prevents everyone from creating offline areas.
Only giving the Owner the ability to edit the Field Maps form, and create offline areas is quite restrictive because if that person in the organisation is away, then all of that content has to be switched over to someone else. It makes sense for redundancy to have multiple users able to edit the form and to create offline areas.
When switching ownership to a different user, all of the previously created offline areas for that web map have to be deleted otherwise it doesn't let you change ownership, which isn't efficient and means we have to recreate the offline areas and get the field workers to download the new ones.