I’d like to see the ability to entirely separate the different drum sounds into their own groove channels, so that I could mix a bossanova bass drum, a rumba snare and a techno hi-hat. 
Not that I am necessarily interested in that particular example, but the point is that a virtual drummer can become limited to predefined styles and patterns. I’d like to have the option to “shake it up” a little bit, to be able to think outside the box while making music. How cool would it be to be able to call in say a frantic bongo play and add a few techno parts to it.
I think I like the option to not think of it as a drummer at all, but more like so many arms and legs playing. Not being able to really emulate a real drummer anyways, considering how many styles and feels a hundred drummers could come up with, I think that “Virtual Drums” fits better (than Virtual Drummer) for a digital drumming plugin.
I don’t think I like the various drum categorizations and semantics to be enclosed as one “drummer”, but rather that all the various drums be considered a single percussion channels to which you can apply sound layers and a groove (or playing parameters) to form a single rhythm part. This way you can mix these rhythm parts very easily to form new beats. You pick a number of these parts to form a set (or “drummer”) that consists of many different sounds and grooves.
I should be able to use a single of those rhythm parts as a program in the plugin.
I hope that made sense there (it does inside my head).