1000 copyright violations
Thats going to be a fun one to face in court...
There is no way they will get permission to make a commercial product like that using all that (not so old) code, especially as you will probably find most of the titles people desire have been handed down from owner to owner and are probably all owned by Ubisoft/Activision/EA by now by acquisition.
I can't imagine those blood suckers being happy that their IP is being handed out commercially.