I agree, it looks good on paper due to a popularity perspective, but the truth of the matter is that the other guy actually won in the deal. While Matt Holliday does have about 25 to 30 home run potential, his OBP was a .350 while Span's was a .385. While thats not much of a difference, as I was looking at your team, I noticed you had a lot off guys offensively that have not had good career AVG.'s. To name a few (Willingham, Hamilton, Either). long with that, you didn't really have a lot of speed either for stolen bases. Span is a career .300 AVG hitter and can swipe about 30 bags. While your team looks like they can clobber a lot of homers, the line up is going to real hurt you in AVG and and SB. Span would have helped in both areas. He may be struggling now, but he'll break out of this slump and most likely go back to his normal self. And in a h2h league, your going to need everything to balance out just in case your other stat departments are having a down week. As for the Dice-K and Dempster swap; again he wins. While both are injury prone and are basically flyout pitchers, Dempster has better control and stuff. If you compare Dice-K's best season, which was in 08, he ended the year with a 2.90 ERA, but had a FIP (Fielder Independent Pitching) of 4.03 and a xFIP of 4.70, which basically means that his ERA was lucky and it could have been a lot worse. As proof of this, his ERA for the 09 season after he came off the DL was a 5.76 ERA. This was accompanied by a FIP of 5.09 and an xFIP of 4.83. Dempster on the other hand, is a lot better. In fact he was the exact opposite of Dice-K's 08 numbers. This year so far, he has compiled a ERA of 4.38. However his FIP and xFIP is significantly lower, standing at 3.58 and 3.63, respectively. With that being said, he is really unlucky with his ERA due to the Cubs' poor defense thus far. His numbers from the 08 and 09 seasons mirror his FIP and xFIP of this year and he will most likely have another good season barring any setbacks due to injuries. Dice-K's and Dempster's career WHIP is about the same around the 1.40 area, but note Dempster has been in the majors longer which implies consistency. Also I have noticed Dice-K has walked a lot more people as of recently and last year. In conclusion, Dice-K + h2h league = bad.
While you may have lost Dempster, your pitching staff otherwise looks solid. Work on that line-up and get some average and speed in there.