Maybe 15 runs for the pitcher, alone, in a vacuum. The team as a whole on the other hand would lose out on creating runs substantially. You seem to be leaving out a much more capable hitter who could bat clean up in the pitcher's stead. I'm not sold on this Kimmi. Maybe you are just using this as an example for a point I'm missing. But It's an isolated, inverse, and out of context way of breaking down any given lineup.
Mookie could bat 9th for all I care and I doubt HIS numbers change all that much (his rbi might take a hit though). He's one of the best young hitters I've seen in a long time. But the team would not be as productive.
I admit there are many games where the lineup doesn't seem to matter for good or bad, for varying reasons. I tend to look at the lineup as one would use a pinch-hitter, but on a much larger scale. You want to up your chances with what's available, and the sooner the better. L/R match-ups, more overall ABs for your best hitters, protection, B/P history (if applicable)... and so on. These mini strategies don't work all the time, but they help increase the pressure on the opposing team, they take advantage of isolated skills, and increase, for lack of a better word... Luck.
All that said, I agree, descending OBP is a nice base to start with. I would micro-manage a bit further. Hell, that's part of the fun.