This have changed with the new set of views in Theater View, yes.
Unfortunately, you can not add new data to this Media Sub Types. So you will not be able to choose Documentaries. this is one of the biggest reason why people is pushing J River to allowing adding data types to this tag. But, no.
You have 3 options as I see it.
1. Mark it as TV Show and live with it.
2. Mark it as Other. But this will give you some problems with Documentaries not showing up in TV. You have to do some editing on the Views. You can select anything here, really. As long as you know what you tag them as. But this will break the automatic tagging for sure. If it ever have worked good enough. No matter what you select for tags, you can still rename and edit the views, so it looks logical on the outside.
3. You can create your own video sub type Library field. I've added one called Video Sub Type my self, and I have full control over this, and my Theater View's is based upon this, rather than Media Sub Type. This WILL however prevent you from utilizing the automatic tagging system in MC16. So you'll have to tag all video files anyway.