If we're talking about ways to shake up baseball, I've got a pretty off-the-wall idea. It's adding relegation (or tiered leagues) to baseball. Here's one way it could work.
Take the 15 teams in each league and put them in one mega-division. Then, organize them by record and make 3 new 5-team leagues.
From 2011 records:
St. Louis 90-72
San Francisco 86-76
Los Angeles 82-79
New York 77-85
San Diego 71-91
Now, you do that for each league and make a schedule that is similar to the one you've got now; the only change is that interleague play ALWAYS focuses on your sister division (lower vs lower).
Playoffs are still 5 teams. This is how I'd envision them working:
The top 2 teams of the top division are the 2 top seeds. The best team in the middle division is the #3 seed. The 1st WC goes to the top team of the bottom table; however, he only gets a WC birth if the team is over .500. If not, the 1st WC goes to the team with the best record (top 2 tables only), as does the 2nd WC.
They would work this way (now 2012 records):
Atlanta 94-68 (playoffs – top 2 in top table)
St. Louis 88-74 (playoffs – top 2 in top table)
Milwaukee 83-79 (stays in top division)
Philadelphia 81-81 (RELEGATED as bottom 2 in top table)
Arizona 81-81 (RELEGATED as bottom 2 in top table)
Washington 98-64 (playoffs – top 1 in middle table; promoted to top table – top 2 in middle table)
Cincinnati 97-65 (1st WC – top record from non-automatic qualifier; promoted to top table – top 2 in middle table)
San Francisco 94-68 (2nd WC – no bottom-table team qualified, best remaining record; stays in middle division)
Los Angeles 86-76 (RELEGATED as bottom 2 in middle table)
New York 74-88 (RELEGATED as bottom 2 in middle table)
Pittsburgh 79-83 (failed to meet playoff threshold; promoted to middle table – top 2 in bottom table)
San Diego 76-86 (promoted to middle table – top 2 in bottom table)
So the 2013 tables would be:
St. Louis 88-74
San Francisco 94-68
San Diego 76-86
Los Angeles 86-76
New York 74-88
The primary advantage to this system is that teams would have more to play for deep in the season. Say you were the 2012 Diamondbacks. Sure, you're 7 or so games back with 16 to go. That might be insurmountable; however, your games still aren't meaningless. You're maybe 2 or 3 games out of relegation range; these games are still important! Even teams like Pittsburgh and San Diego have something to play for late in the season.
The system also rewards continued success. Being in a top table means you play better teams (more ticket sales) and makes the path to the playoffs easier (each table has easier playoff restrictions than the year before it). These are huge bonuses in my opinion. It also masks the weaknesses of teams in the lower tables, because they will play slightly more shit teams.
The two main disadvantages with these systems is that a) the travel becomes ridiculous and b) you lose historical rivals. I don't care about either of these; teams have jets these days and each team plays each other team every year anyways.
You could also do this by merging all 30 teams together. I like this idea slightly less but am not sure why. In this case, you'd could have 3 tables of 10 teams, with the playoffs being 6-3-1, and maybe 3 up/downs for each table. Haven't thought it about it all that hard.
Let me know what you think.