James Click has a subscription-required article up at Baseball Prospectus about lineup orders. There actually wasn't much new there (he didn't include stolen bases, which along with other baserunning skills could make a huge difference in theory), but the following blurb did catch my eye:

The implications of this is that even if a general manager knows exactly what each player is going to hit in a given season, the 95% confidence range (typically two standard deviations) is about 160 runs. This is something that we don’t talk about too much, but think about that: you know exactly how each player is going to hit this year and your team could win 84 games or they could win 100. That's just statistics for you.

Again that's assuming you know how everybody's going to hit, which of course you don't, or at least I don't. Throw in the inherent difficulty of predicting pitchers and any optimism should be guarded, although I'd short the Cubs if I could.