I don't think Flynn is on the critical path any more, given the Mueller report is complete. He's just some unpleasant lying criminal guy who traded his country for a contract, but, given his political positioning, was probably too dull-witted to understand the full implications of it.
To be frank, generally-speaking, I also find plea-bargain lawyering undermining of the basic premise that everyone is equal under the law. So I welcome the fact that he will face the consequences for any crimes he is alleged to have committed.