The true fans want to see both games and I suspect you will alienate a lot of them if you prevent Ghosts being made (even if it's through a justified win in court). I personally wouldn't be at all happy with any "winner takes all" scenario no matter which way it goes.
If only they had something to show for Ghosts... You do realize that there might not even be a single line of code for Ghosts? What if there weren't even an intent to write it. Have you ever assumed that possibility like you assumed a lot of other things?