I believe that we all knows this and believe it to be true. And the Sox have shown this recently especially with the signing of two top closers only to find that neither could pitch ( at least while here ).
The Sox pen was # 26 in MLB in 2015. A major overhaul is necessary. While technically you are correct when saying the Sox do not need a closer, that they are somewhat strong there, we will need a new closer and I say strike while the fire is hot. He is one of the best and he is available NOW. I disagree that a closer of equal value can be had much cheaper. I say with Paps getting his deal, Miller getting over-paid by NY, The Sox doling out $9. mil to Koji, well, maybe this is the new closer economics. The Sox need pitchers in the pen PERIOD. Which end they start at is far less important than what they finish with.
The team is better. Maybe not better enough to justify your approval. But it has gotten better.