Liam Neeson? Bruce Greenwood? Eddie Marsan? Marton Csokas? (the guy from Into the Badlands) They're all great actors plus Tony Goldwyn whom I loved seeing in a political role like this, Scandal (nice series, check it out.) The cast is simply talented and awesome!
The movie was not too long, nor too short. it just felt right. I loved every bit of it.
Joan Felt, daughter of Mark felt describes her father as an "American hero". You're goddamn right. Some may say he probably did it to be the director of the FBI. Others say he did it for good of the FBI and the country ultimately. I think the latter, he did it out of institutional loyalty to the Bureau. Awesome film.
Liam Neeson does a fantastic job- in my opinion- in a role that is not action related. He would do well if he takes more roles like this. (I thought he did well in Third Person too).
Finally, this is just my opinion. I enjoyed this very much!
PS: If you are more interested in Mark Felt, I'd recommend you read his book **A G-Man's Life: The FBI, Being 'Deep Throat, ' and the Struggle for Honor in Washington**
You could also go on Youtube to hear the taped conversation of POTUS Nixon with Mark Felt "Deepthroat'' and other taped conversations of the president suspecting Felt to be the source leaking information.