If I remember, Janes appeared before CFS, so it can't be a rip-off.  I remember the graphics in Janes being top-notch for the time.  They certainly out-clased FS due to the localized nature of the sim (not having to show the whole world)  The virtual cokpits were actually better than the current CFS is now too...  Think about that one! Also, MS is just now putting ground attack missions into CFS, where Janes had it to begin with.

I'm not saying Janes is a replacement for the current sim.  I just think there is more than a little in common between the two and for my money, MS could do a much better job considering the time and money involved here