I think the key question is whether the iTunes category is required
to be a
value from a controlled taxonomy (often necessary for commerce
reasons), or
whether it can be any user authored category.
Agreed.
If it is a controlled taxonomy, then the taxonomy should be defined
in the
specification, including rules about case-sensitivity of the values
etc., or
should normatively reference a list at the necessary commerce site
for the
controlled vocabulary.
Not necessary. A lot harder to update. For example if your
applications loads dynamically the categories from a file, more than
an harcoded set of categories.
If it is a user authored category, perhaps consider simply using
"tags",
which have been shown to be a very successful way of publishing and
indexing
user authored "categories" / keywords etc.
