Astros being in the AL West would be fairly groundbreaking, as well as the fences being moved in at Safeco Park, possibly the new free agent system as agreed upon prior to the 2012 season. I dunno, I just think those are the three MASSIVE changes between The Show 12 and The Show 13.
you still buy the game fishnips. you will 'fishbelly ache' all march and april while advertising that people should rent the game from blockbuster to try and keep your job open. then you will buy the game and in may and act like you are doing your part in not supporting a new game on release because they didnt add warp levels and mystic potions.
its a baseball game made by the same people each year. and like it or not they are the only gig in town now, and they are damn good at what they do. support them so you dont get stuck with an EA Sports baseball game in the future
"Too many Urkels on your team, that's why ya Winslow" ~ Kanye West
Granted its not all massive improvements, but that assessment can be made of almost every multi-game franchise.
Madden: Football, only its under a license for the likes of the actual players for NFLPA and the likeness of each team.
Blitz: Again, Football, not under license but is an arcade version of the sport.
Most "Modern Military Shooters": All first person shooters and most are heavily scripted. The most infamous script being not being able to open a door on your own when the AI is able to open it solo without hesitation. In the end, its still just Point cross hairs at target, shoot, repeat.
MLB The Show/MLB2KXX: Baseball. Recycled content/features, but (in the case of The Show) Attempts to come as close to the actual sport as it can with association from MLB Network while 2KXX is and always will be more of an Arcade style of baseball.
Hell, even Scribblenauts is just recycled core concept (Solving silly puzzles in any matter possible while also keeping it to words without negative connotations.) when it comes to its sequels.
Point is based on the limited options available that include our favorite teams and favorite player(s) while also being the most modern, its going to be The Show or bust until EA can scrape something together and launch it successfully without attempting to milk it heavily like a majority of their games which I don't find likely to happen.