Average miles to travel within Division / within League:
AL CENTRAL = 415 Miles / 996 miles (1315 average)
AL EAST = 710 Miles / 1,258 miles (1315 average)
AL WEST = 1,094 Miles / 1,691 Miles (1315 average)
Within their own division, CHW travels an average of 312 miles, while SEA travels an average of 1,280 miles. And that is within their division. CHW's average of 931 miles of travel with ALL AL Cities is a far cry less than what SEA does from within it's own division. This is a financial cost and a significant one at that.
Sure, the travel is easier for certain cities, but it is grossly unequal. And maybe you never will get SEA, LAA and OAK to be equal. But a balanced schedule pretty much makes the over 12 cities equal.
If you really want to fix it, geographically align the cities (i.e. all West Coast teams in the same league). Tampa and MIA should be together. You want rivalries, put the Mets and Yankees in the same division. Cubs vs Whitesox. Proximity makes the rivalry, not the divisional play.