If Flynn cuts a deal then he has something meaningful on somebody. It’s probably trump or Sessions. Though sessions seems to have been reacting in horror as it all played out and didn’t seem to start covering it up until later.
I agree that the piece of information Flynn turns over (or at least what gets leaked) might not mean much to trumps diehards but literally nothing will mean anything to them.
It’s actually pretty phenomenal how far the trump campaign has changed it’s story. It went from “nobody talked to Russians” to “ok we talked to Russians but it was normal transition stuff” to “ok it wasn’t normal transition stuff but nothing came of it” to “ok, something came of it, but we didn’t know something was going to come of it”. Literally, the piss tape could drop and Russia could pay trump off in cash on video and they would say “taking money just makes him smart, Russians are our friends anyway, it’s ok to pee on hookers if you repent, and besides Hillary killed Vince foster.”
If you approach it from a view of “this will finally convince his supporters or it’s disappointing, you will always be disappointed 100% of the time.