As others have said, the main thing the Sox need to do is get much better at developing major league quality players through their farm system. As was discussed in a minor league thread, they haven't developed a quality major league position player since Aaron Rowand was drafted 15 years ago.
Until they get their act together in this regard, I don't see them being a consistent playoff team. Their key to success over the last decade or so is to find good players off the scrap heap. That's a useful thing to be able to do, but it can't be the cornerstone of a team's attempt to compete. The Sox have also shown a willingness to spend on veteran players at times (Dunn, Peavy, re-signing Konerko, etc.). However, this usually isn't enough to put them over the top when there is almost no organizational talent to fill the remaining holes.
The Sox are the only one of the original 16 MLB teams who have never made the playoffs in consecutive seasons. In 18 full seasons since the 3 division/wild card format started, the Sox have only made the the playoffs 3 times. Three stinking times in 18 years out of the AL Central. That's unacceptable.
Perennial playoff contenders spend money on MLB payroll AND invest in a good farm system. Sox ownership has simply not shown either a commitment or an interest in committing to both. It's been about 5 years since KW had his "shakeup" of the Sox farm system - when they hired Buddy Bell. It's been 5 years and i'm still waiting for enough of a talent core to help put this team into the playoffs.
Maybe the new CBA will change things, maybe there's talent already in the pipeline that'll burst upon the scene in a couple of years......we'll see.
In the mean time, this team is mired in 2nd or 3rd place, attendance has fizzled after 4 seasons with varying degrees of disappointment, and Sox fans bear the brunt (not from ownership, but from the media and from other fans) of not supporting an uninspiring team.