I really like the idea of a D league. Lots of details involved to make sure it's balanced correctly, but being able to train more players should be a valid strategy. Some teams IRL focus more resources on their farm system than acquisitions. Others are in a rebuilding period of years. A D-League that is a cost decision to make would add another fun bit of strategy and planning. Your suggested costs per week also seemed a bit high to me, but the cost should be high enough to make it a decision that every team won't opt for. Also, potentially the cost per week should be adjusted based on the division you're in?