The area element is sorta in a class with the input, button, command, menu, and bb elements in that it has an attribute with an enumerated value, and several variants according to the value of that attribute. In the case of area, it's the shape attribute, and the datatype of the coords attribute on area varies depending on the value of its shape attribute.

It thus makes some sense to have the different variants of the area element defined with different element patterns.

Note that I'm not suggesting this change out of some kind of purist motive consistency or completeness, but because having the content model defined in separate patterns makes it easier to post-process the schema (e.g., to generate documentation from it) without needing to result to doing special-casing (which lacking this suggested change is what I find I need to do).