Jang,
Don't get me started on the risks of users formatting their own structured documents. Directly applying formatting properties is only one way to do so. Others include manipulating white space (particular spaces, non-breaking spaces, and forced returns) and tag abuse (choosing an element that is not logically appropriate but produces a desired appearance).
I agree completely that these are techniques that should be avoided if at all possible and with your approach of demonstrating how they fail when the material is re-used, when a template is updated, when material is saved as XML. Neverthless, some organizations prohibit such techniques; others rely on them. FM was designed to support both groups.
Consider for example, final production editing that tweaks page breaks, possibly adjusting line or paragraph spacing or font size to do so. Should elements and attributes be defined for this much control? Maybe, maybe not, especially if the relevant settings are to be restored to the defaults for the next version of the document.
Or consider a writer who was requested an EDD enhancement that has been approved. What should the writer do if his deadline is before the EDD developer's?
--Lynne