As a V1 admin,
I would like to be able to add custom fields to issues, portfolio items, and backlog items that function like the V1 tag cloud
so that I do not have to guess what select items should be in the drop-down list before I have knowledge of what will need to be entered and to reduce the friction associated with getting my users' list items added to the system.

As a V1 user,
I would like to be able to add new drop-down items to a multiselect custom field
so that I can add items as I think of them without the friction of an approval and administrative process.

As a V1 user,
I would like to see similar drop-down items to what I am typing or adding in
so that I do not duplicate the meaning of existing drop-down items.

JIRA has the concept of a label type for custom fields that work similarly to the V1 tag cloud but is able to be utilized in custom fields.