For Weekly Leagues, I prefer H2H. I'm in a league that allows 1 sub per week that is run through FanStar, but they're a pay site. To the best of my knowledge, neither Yahoo! nor ESPN allow any substitutions if they are set to weekly. I don't know about CBS.
For H2H Weekly, 2-start pitchers are interesting. Starting pitching in general, really. You can't decide on Saturday based on where your ratios are on a questionable start, so on and so forth. You need to make the decisions a week in advance, and sometimes a PPD will push a great Sunday start you had into a miserable Monday match up the following week. The intricacies are small, but as you indicated initially, growing up it gets more and more difficult to commit time to this. I used to play in 6 - 7 leagues per year, and now I'm down to just 2, one of which is weekly, and I've never enjoyed playing more.