The Cubs are not good defensively. They are not good on the base paths. They do not pitch well. And they are average offensively. These constitute the four elements of baseball.
We get excited when we see Darwin Barney defending, Starlin Castro running the bases, Matt Garza pitching, or Carlos Pena stroking a fly to the bleacher; but these are just small elements of a synergistic effort. Good teams have more than just a few exciting players and plays, they have whole team efforts that excel in at least 3 of the 4 elements of baseball.
Note how the Cubs rank near the bottom on these four elements:
Yeah, Barney is good defensively, and Kosuke Fukudome seems capable, but the team as a whole fails defensively.
The Cubs pave the way for bad base running. If Castro or Fukudome spend some time on the DL, expect the Cubs to push for new records in bad running.
Our pitching, once average, has slouched into terribleness. I have before mentioned how teams in contention need more than 5 starters; they need upwards of 7 capable starters (meaning 2 to 3 above average or excellent pitchers, 3 to 4 barely above average pitchers, and 2 to 4 average-to-replacement-level pitchers).
Which is funny, because at one time this off season, the Cubs had 4 good starting pitchers (Carlos Zambrano, Ryan Dempster, Matt Garza, and Randy Wells), 3 above average pitchers (Andrew Cashner, Carlos Silva, and Tom Gorzelanny), and a slew (5+ at least) of replacement level (or worse) pitchers (Doug Davis, Thomas Diamond, Casey Coleman, Jeff Samardzija, and so on).
The Cubs then proceeded to shed their not-good pitchers, slimming it down to the mere five they intended to trot out every day and pitch 200 innings each. Bullpens hardly matter when the starters are getting blown up.
The Cubs have been average hitters since forever. This year is not much more of an exception. The Cubs stats are just below average offensively, but with Marlon Byrd returning and Aramis Ramirez heating up, we'll be average again in no time!