I get both sides here. I want Baldwin for the upside and better shot at a title. I also dont want to lose guys, whether they are fan favorites (Joey, Goldwire) or because we are losing 4 year building blocks (Coleman).
The problem with both is accurately predicting the future. Baldwin is great until he chases off Coleman, is a liability on D, isn't physically ready for high end competition, etc. Then again, his elite shooting could prevent an 18-19 disappointment and or allow for an injury to Paolo, AJ, or Mark from being disastrous.
As for the "building" blocks, DJ, Brakefield, and Goldwire say high. In many ways, DJ had no business leaving. In a "normal" world, he is a 3/4 year guy. Brakefield got good minutes, was relatively successful as a non star recruit, and looked like he loved being at Duke. He would have gotten 20 minutes a game this year, and was set up to be a starter or 30ish min a game reserve years 3 and 4. He was that building block who left anyway. Goldwire came in as a "scholarshipped" walk on. Got way more minutes than anyone imagined, and left. I don't begrudge any of them for leaving.
My point is, with the transfer rules as they are and kids leaving who are projected to go undrafted there is just too much dumb luck involved no matter what the staff does.