The problem here is that it seems the DOJ hasn't provided sufficient information in its filings to reinforce the idea that the DOJ was guilty of wrongdoing in the case. If anything, I'd say there's a good chance they want to drop the case to AVOID making any admissions that should really be brought into the public domain.
FWIW, at the time he pled guilty, he was being represented by a law firm where Eric Holder was a partner. Based on the fact that the law firm that represented him was headed by a former head of the department that spied on him, I think that his plea should be thrown out based on the fact that his attorney had an undisclosed conflict of interest.
Regardless, any argument that he should not be freed at this point is an argument in favor of tyranny.
Flynn was railroaded. Its time to derail that train.