When stumbling around the web trying to find out the correct usage of ARIA roles I found this great article about ARIA Landmark Roles on A List Apart.
Landmark roles are a set of eight ARIA roles that serve as key milestones, allowing AT (assistive technology) to map the lay of the land of an HTML document.
There's loads of information on the ALA blog post, but what it did suggest is that roles such as
form aren't necessary when used on elements that have those as default behaviours. For example:
<a href="#" role="link"></a> <form action="#" role="form"></form>
So that clears that one up. Next!