I know Garrett won't go anywhere but he really needs to go. His game management issues are killing us.
I also doubt Linehan goes anywhere because just like Jerry with Jason, Jason is "comfortable" with Linehan, and God forbid anyone challenges the norm in Dallas.
What might be more realistic is a new QB coach to work with and push Dak.
I'd also see if Dak could spend some time in the off-season working with Aikman. Troy was was rumored to be one of the most accurate QB's (remember all of the stories about perfect practices and no dropped balls?). People here are ready to give up on Dak but he has some athletic and leadership tools that are valuable. He just needs to really improve his accuracy.