Level of hapiness of the players isn't such a bad idea, this will open to us a new dimension, because players could be finally a persons with theirs own needs..
But it is complicate to apply something like that to the game and keep it intuitive... in that case there should be another preferences - like ambicious or loyality of a player. Willingness to go to the transferlist and so..
In my opinion it is a great innovation, but on the other way - it can creates more damages than it seems
I think this is a poem of a far future