No offense, but I would think it's easier to program in to have someone come into a game to face a LH batter in the 8th inning, than to program in to have someone come in to take a faceoff with "x" minutes left if you're trailing by "Y", then immediately get off the ice for a line change. Heck, right now, faceoffs are only taken by the guy on the ice that's taken the most in RL.
Baseball is a game that stats work perfectly in, which is why it's easier to program in more variables. Just compare a hockey box score to a baseball box score. Which one gives you a lot more info? Besides, for baseball, you've got stats in nearly every category going back 100+ years. For hockey, you've got less than 30 years for a lot of stats, less than 15 for things like ice time. Most of us "know" that Joe Malone played nearly 60 minutes a game back in the early days, but you don't have exact numbers to prove it. However, you do know that Babe Ruth hit 60 home runs in 1927 or that Ted Williams hit .406 in 1941. The stats are there.
Sorry for the rant, but Mike Welch does plenty enough for us, and I can't stand it when people A)insinuate that he doesn't know hockey and B) try to compare baseball stats to hockey stats, because there is no comparison at all in the level of complexity.