1. I don't agree with tico in evaluating this (with Garza and Maholm) as a very solid better-than-average rotation. tico has Garza as a 1.5, Dempster as a 2.5, and Wood/Volstad/Wells/Maholm all as 3.5 starters. If you add up those numbers, it averages out to 2.9. Right around average, just a shade better than average.
It could work out that way. But a roughly average staff is average. And I think it's kind of optimistic to be expecting all those guys to be 3.5's. I think the vast majority of teams figure that their 4th and 5th starters have a chance to be 3's if things go right. But a lot of the bad 5's in the league are would-be 3's who aren't pitching that well, due to injury or slump or whatever. Low-stuff starters like Wood/Volstad/Wells/Maholm don't have the same margin for error that healthy Wood or Zambrano had. There is a fair chance that one of them will be given a rotation job but will pitch like a 5.
2. Another factor, of course, is the defense. br has noted that most of the Cub starters were victims of poor defense. While that may improve to some degree, I'm not expecting some radical upgrade in defense. Soto is still Soto. Castro might improve, but he's still Castro. Byrd isn't likely to get a lot better. WE'll upgrade significantly at 3B, but much of that will be negated by downgrading at 1B. Overall I think the infield defense might be only modestly upgraded. Outfield might be different, but that depends on what Hoyer does in left. At present it's still Alf.
3. One other thought on pitchers and ground-ball contact guys. We tend to look at ERA's and FIP-ERA's and the like. But a team goal is overall run reduction, not just earned run reduction. Isn't it true that contact pitchers and ground-ball pitchers give up a significant number of extra unearned runs over the course of a year? If you throw 200 innings and K 100 guys versus 200, of course those extra 100 outs you're expecting the fielders to make are going to involve some errors. Your run prevention is going to be better if you K 100 guys rather than expecting Castro-to-LaHair to get those same 100 outs. It's also true that fly balls are less likely to be dropped than ground balls. Groundball contact pitchers naturally are going to source more errors and more unearned runs.
I disagree. Dempster is a -2/+3 starter. Wood, Volstad, Wells (and if added, Maholm) are -3/+4 starters. May not seem like much, but I think it's significant.
We may not matchup well against some teams' 1 and 2 guys, but I'm pretty confident that 3-5 we'll be much better than most teams. It's sexy to have that ace pitcher, but you can't pitch your ace every day. Scrubs have to make starts, too, and when another team is starting a scrub and we have someone much closer to league average going, that's a significant advantage.