I think there are many very practical uses for games like RTSs, Shooters and RPGs. Especially when we are talking about a console environment where you don't have the wealth of "buttons" that comes with your keyboard.It's more a matter of practicality (or practical uses) then come up with simple uses.
As for shouting at the game. Well, I obviously can't speak for everyone, but I don't know of many people who don't "interact" verbally with their games already.
Certainly, I think if there is any validity to this rumour then it is most likely just that Nintendo is making some sort of mic standard and providing voice recognition libraries to devs.Room for improvement, sure. However there has been mature technolgy in voice recognition for a long time. I don't think Nintendo is going to come along and re-design voice recognition to finally make it work perfectly. That I just don't see happening.
Speech recognition itself can still improve, but getting back to those practical uses... To do some of the really neat things one might imagine with voice control requires more than just being able to pick out the words a person is saying. You also need to understand what these words mean, which can be a very complex problem by itself (if you want to move beyond just simply barking out commands).