Explain the problem as you see it
I wish that hiding fields was specific to supertags, not to the field itself.
Why is this a problem for you?
For example, I may have an >area field that is more important for one supertag than another (I may want an area field on every #task, but not necessarily on every #book or #movie). But if I want to hide the field on one supertag, I must hide it on all of them.
Suggest a solution
Give each field under a tag a hide field menu on the right with the options localized to the supertag.