They didn't take it away from the team with the best record. It used to just alternate leagues, so this way at least it's actual being decided on the field, even if it is just an exhibition, rather than just depending on whether or not it's an even or odd year.
I didn't realize it alternated leagues before. I just think that if you have the best regular season record and make it to the World Series you should be rewarded with home field advantage and not have it predetermined by which league wins the ASG.