This is a good point. I don't think it should be too advanced, because they are supposed to be quick fire responses, but simple things like video, bold, italics would be useful.
I've also has similar experiences with users. They also expect to be able to attach a file to a comment or direct message like you can in other fields where they can enter text in the system. I have to tell them to post it separatly and then link to it in the comment or message.