Right now the league that wins the All-Star game gets the "home-field-advantage" in the World Series.
I think a fairer and more interesting idea would be to award 'home-field' to the league with the most combined victories in interleague games. Just add up all the interleague victories by each team in each league. If tied then the winner of the All-Star game gets the tie-breaker.
I think people would be interested in which league has the most wins. It would make each inter-league game count more and also isn't it a fairer way to determine who was the superior league as opposed to the All-Star Game? People might pay more attention to who is winning all of the contests.
I also would drop it down to 4 or 5 series per team. The A's and Giants and any other two team area should play 2 series as they are now but otherwise they should cut down some of the other games.
Think about it, if you live in Oakland and just HAD to see the Marlins you could just go see them in SF.