It's only as limited as that if you 1) ignore everything being leaked out of the situation and 2) know nothing about how corruption/organized crime/financial fraud prosecutors do their jobs. which is exactly what mueller is.
So yes, if you read only the published facts and forget everything else you know about the world, you could imagine that this is nothing but a minor charge with no significant implications for anyone else connected to the investigation.
So you basically immediately assume that Flynn's just going to drop to his knees in tears and tell the investigation absolutely everything? He might do that, by some slim chance, but I'm saying that we aren't sure about what he's going to say at this point, and therefore it's too early for us to speculate.
I'm saying he already did.
And why, may I ask, do you assume he already did, if we have hardly any information about it either way?
Because he was only charged with a single count of lying to the FBI, and there are no plans to charge his son with anything either. If he weren't going to cooperate, he would be facing a dozen or more charges about various lies and financial arrangements over the years, like Manafort is.
Also, because he pled guilty. The prosecutors have what they want from him, and so he is being allowed to plead guilty to a single felony.
In short, nobody's actions in this circumstance make sense unless there is a significant deal behind the scenes and Mueller's office has the testimony it wants. Flynn wouldn't be charged, nor would he have pled guilty, otherwise.