Ignoring the obvious ones like ET, Superman 64 and Big Rigs;
SimCity 2014 (disgrace to the franchise)
SimCity Societies (ditto)
Star Wars: The Old Republic (disgrace to the KotOR legacy, should have been KotOR3)
The Lord of the Rings: Return of the King (keep the movie, the movie's awesome)
RollerCoaster Tycoon 3 (textbook example of why gameplay > graphics, as RCT2 > RCT3 x 1000)
So basically, bury EA and the others that went on ruining franchises. I also wanted to nominate Assassin's Creed because of boringness galore, God of War Ascension because it's broken and Grand Theft Auto IV because it was utterly disappointing. But, alas, at least I had minor fun in those games...