While I think it will be a decade with a huge impact on the sport, I do not think it will be any bigger of a decade than the rest. Here is my opinion why.
1.A-Rod chases No. 763. If he gets it where will he rank?
He's going to get there... at the very least he's going to get close. However he's no different than McGwire, Sosa, Clemens, or the others. He is, and will forever be linked to steroids in baseball. He may get the record... but he will be perceived as a cheater, just like the rest. Doesn't matter... he won't hold the record for long... why?
2. Pujols chasing big numbers. AKA a lot of digits.
This is why. Albert Pujols is the absolute best hitter I have seen in my entire life. Obviously I wasn't alive for Ted Williams or even Pete Rose when he played so they're disqualified from my comment, and I will always regard Ken Griffey Jr as having the sweetest swing and motion in the history of baseball, but Pujols is a machine of a different breed. If there is ANYBODY and I mean ANYBODY out there who is going to give serious chase to the HR Record, whether it's held by Bonds or possibly A-Rod, it's Pujols. I just hope he can avoid the steroids allegations between now and then. He's clean though... I'm fairly sure of it.
3. Jeter rides off into the sunset. Where will his place in history be?
Derek Jeter plays for the Yankees at the wrong time. Seriously. For the demeanor that this man possesses with his love for baseball and its history it's a damn crime that he plays in today's age and not in baseball's glory day. If a time machine exists, I want Jeter to be the first project. It's time to send Jeter back to Murderer's Row where he belongs. In a dark period on baseball, Derek Jeter is a lone beacon of excellence.
5. Who will succeed Selig as new commissioner?
Who cares? Selig is the absolute worst thing that happened to Baseball and just about anybody who replaces him as Commissioner will do a better job. Except Gary Betteman. Fuck that guy. Seriously though, I don't know? Maybe the owners (probably not due to the traditionalist stance of baseball) will reach out to somebody outside of Baseball (Condy Rice?) or maybe they'll figure that since a former owner of the Milwaukee Brewers (Selig) was given the chance to fuck baseball up, that maybe they should give that chance to another former owner... George W. Bush.
6. Barry Bonds, Piazza, Clemens, and Sosa all become eligible for the 2013 HOF? The big ones are Bonds, Clemens and Sosa. Are they worthy of a Cooperstown induction?
Mike Piazza is a second ballot Hall of Famer. I say second ballot because NOBODY gets in first ballot in baseball. Greatest hitting catcher of his generation and MAYBE of all time. Bonds', Clemens' and Sosa's numbers all dictate HOF induction, but they'll never sniff the Hall. If they do... then it's time to reinstate Pete Rose and elect him in, and it's time to elect Mark McGwire in. All or none.
7. Expansion of instant replay.
God I hope not. Unlike football, basketball, and hockey which all use INSTANT REPLAY to my liking -- I never wanted it for baseball and never will. Baseball is different, it's "pure" (or at least it was), and it shouldn't be ruined by having a television screen correct "Final" decisions. Umpiring and the prospect of "human error" having an affect on the final outcome is what makes baseball in the clutch amazing. Somebody gets hosed on a bad call? Sorry -- that's baseball. Having the technology to reverse a call just takes baseball away from the pastoral setting that makes it so great. I only hope that the MLB Owners vote to eradicate Instant Replay entirely.
8. MLB Advanced Media continues to rise?
No brainer.
9. Financial Health of Franchises?
Say goodbye to Tampa Bay and Oakland. Minnesota has a new stadium coming in if I'm not mistaken. The Marlins move into their new home in 2012, and most other teams will be fine. Tampa just isn't a big enough market in the state of Florida -- despite it being Florida, and Oakland is getting a shafting by Alameida County. They're going to lose the Raiders (again) too if they don't build a new stadium soon.
10. The Rising Cost of games?
I think the global economy will eventually cause Baseball clubs to scale it back a tad with ticket sales. Obviously, the Yankees will continue to rape their patrons due to the new stadium and well, it being the Yankees -- but if smaller market or mediocre teams want to survive the next 10-20 years (Baltimore, Atlanta, Florida, Arizona, Cleveland, Colorado, Texas, Minnesota) they're going to have to improve gate. Single game ticket sales aren't as outrageous as people make them out to be -- but when you take a family of 4 to the ballpark for a game, and get 4 hot dogs, 4 sodas, and 4 souvenirs you're going to spend a pretty penny.
This is why Minor League Baseball in many markets is so successful. I'll give you an example: I grew up in Central Pennsylvania. In the small city of Altoona, the Pittsburgh Pirates have a AA affiliate called the Altoona Curve. They came to town in the mid 90s and have what many claim to be the most beautiful park in Minor League Baseball (right field has a roller coaster directly behind the wall!). Single game tickets along the 1st and 3rd baselines in General Admission are 4 bucks. 4 dollars! At the AA level the baseball is excellent, the atmosphere is incredible, and the Altoona Curve are reknown for their gimmicks (ie: Frivolous lawsuit night). Stadium is always packed and money comes rolling. Most expensive seat is like, 12 bucks.
If MLB would just scale prices down a bit (I know, it's hard to make a penny when you're paying 25 million to somebody who only sees action once every 5 days) the fiscal health of franchises wouldn't be an issue.
All in all, I think the biggest story of this decade COULD very well be the possibility of a real World Series with the MLB champion taking on the Japanese Champion. This has been done "in exhibition" the past couple of years -- but if it comes to fruition, Baseball will EXPLODE once again in America and truly return to pre-1994 strike levels.
Just my .02