First thing I would do: MUTANT LEAGUE SPORTS. Every sport EA has a license to make, use the engine and make Mutant League games. All those licensed teams in their sports leagues are gone, and the players are replaced by zombies, orcs, animal-men (molemen, werewolves, etc.), whatever the Creature From The Black Lagoon is (merman?), mummies, cyclopses, ogres, goblins, skeletons, et cetera. They should be cool-looking, but not quite scary, we're still trying to make the game appealing and not get sued by the guys who made Blood Bowl. Also, incorporate the Juicing aspect of Blitz: The League and modify it to enable you to modify players, allowing for them to have four arms or eyes in the back of their heads or things like that. Also, story mode. The coaches are spider-people, the announcers are cycloptic heads in jars. Finally, tackles/hits/etc., there's a chance (CHANCE being the key word, it doesn't happen every time) of tearing off limbs or heads, but it's treated as a bad injury and you can use chemical pods to have your players regenerate faster with the downside of it hurts your players' stats.
And then...no, that's basically bullet point #1.