In 1.9, the comment box used the html editor. In 2.0, tinymce is not used. In the M&P database, I had encouraged moderators to make comments in red text. Technically they can still do so but they have to manually handle the html (i.e. something like, <font color="red">Moderator comment</font>. Perhaps this is just one of my settings but as far as I can tell I am using html editor when editing text and advanced web features. So I consider this a slight loss of functionality in 2.0.
Also, in 1.9 there was the ability to edit comments. In 2.0 it appears there is only the ability to delete a comment. I'm attaching two screen shots - one from 1.9 and one from 2.0 to demonstrate the differences.
Peace - Anthony