It is too simple to trade between teams and make alliances against the others. Even if you will trade adequate or "weaker" player, he will be different and maybe just on the skill where you need. The other team can make things the same way.
..and you can trade and trade, this one will be better there and this one there, without any other expenses...
I think that this game have more other potential than to be switched into boring business manager.
I like the idea about supporting transactions between the teams in the division. Maybe it could be allowed for the loans or different things, I don't know, however direct trading is a step into a wrong direction.