None...
IMO, make 10000000000000 sequels of whatever you want, If I dont like it, I will ignore it. End of story.
Never undestood the hate towards "milking" a franchine. You know, maybe you can ignore it and let the people who enjoy the games alone? This specially applies to those who complain about sequels SOLELY based on the fact than it is a sequel, even whit the game itself not begin out, or there begin videos of gameplay, or ANYTHING AT ALL.
If you tell me than you hate sequels because you feel than the companies are just in for the money regardless of the quality of the game itself, well thats a bit more understable, but a LOT of people just rage at sequels just because they are sequels...
Lets take COD for example. I like those games, and for me, at least, they can make COD games every single year and I will be fine, if you dont like it then ignore it instead of raging all over the place witch just gives the game free publicity (Well, in COD case its not like it does make that much difference, but my point still gets across). Will I get tired of COD? Maybe. Then I will just move on to other games. THE END.
Excuse the lack of proper grammar, English is not my lenguage.