I suppose that idea of "older gamers being unfit", is grounded in a valid notion.
I myself know that I am not so much "unfit", as horribly underweight from illness.
So I am in no place to argue the negative xD .
In regards to precise-motion gaming, it would certainly be enjoyable.
However... the games need to be vastly more immersive, to warrant purchasing extra motion-sensitive equipment (speaking of the PS3 & Xbox 360).
In terms of Nintendo; they're doing things rather well for now (in my opinion that is.)