I would love to include trades, and it's on my to do. I'm currently thinking of how to best handle transfers between teams in different leagues. It would not be realistic for players to accept a trade to a lower league level so as you said Nicck37 you could limit trades to the same league. But I'm also thinking of creating a different type of game world that is more North American influenced that the one today. This new game world should include both trades, affiliate teams and drafts.
Hopefully I can release something soon. Thanks for your feedback.