In order to maintain data quality it would be helpful to allow users to assign tags to contacts/opportunities but not actually be able to create new ones.

At the moment I can either stop a user from assigning and creating a tag or just view tags.

The issue is that with the current approach it reduces data quality as some users are creating new tags where its not needed, or creating miss-spelled tags or creating duplicate tags as they are using a different word for the same thing.