Baseball's expansion decisions in the past 15 years have been disastrous. SO many cities in the US would LOVE a major league team (New Orleans, Portland, Norfolk etc.) and MLB awards teams to Miami and Tampa Bay. Both decisions were disastrous. Florida demolishes their team after every decent season and has one of the lowest payrolls in the game, and plays in the second ugliest stadium in baseball. Tampa has been a perennial loser, draws no fans, doesn't have any players any non-gamblers have heard of, and plays in the ugliest 'park' in the game.
Colorado hasn't been all that much better. Sure, they were exciting at first and drew a lot of fans, and their ballpark is pretty. But they too have been doormats for most of their history, and most importantly, have done almost as much damage to the statistical integrity of the game with the altitude and inflated run-scoring at Coors as Barry Bonds' inflated head. That baseball didn't anticipate the skewing of numbers at high altitude, (and stupidly thought that making Coors the biggest stadium in the game would even things out, yielding a ridciulous number of singles and duoubles) is more sign of their shortsightedness. You wouldn't put a baseball stadium in the ocean; you can't do it in the high heavens of Denver either.
Only decent selection has been Arizona, a solid, successful stadium with a pretty park and a decent history of success, including a WS win. Baseball should unquesitonably contract -- not historic franchises like the Twins -- but perennial losers with owners who don't give a crap like the D-Rays and Marlins (two WS wins notwithstanding).