I also wouldn't go back too far. Results from the 80s are really not relevant at this point; spending rules have changed, luxury tax, etc.
Maybe stick with this century.
And our sane Yankee backer above has a good point about losing seasons being taken into account; just off the top of my head it would impact the Astros ranking as they several horrific years early this decade while they were building their current juggernaut.
Might tweak the win totals slightly though. 82-80 gets a point while 80-82 loses one, even though they are virtually the same season? Maybe with a 60-65-75-85-95-100 split, or something like it.