1. There actually already is HTML output. My idea is that most people will likely copy/paste from HTML or a Word Doc to combine with their collaborators. From that perspective, PDF feels too 'finished'. And yeah, as someone else explained, I'm a PM on the Office Online team :)
2. This is great. I'm working on supporting different lists than just Nielsen's heuristics (including being able to create your own custom list). Unfortunately the one you linked to is quite long and might be quite lengthy to have in the sidebar. I'll think about that though.