The whole storyline is setup for S3. You don't think the mysterious death of the VP's chief of staff right when he becomes President will be the start of Frank's downfall?
And the point of the Freddy episode to me was, just before everything comes to head, we are shown for one last time that Frank truly doesn't care about anybody.
What I liked about S2:
Underwood vs. Tusk was good to me. S1 there was no worthy adversary for Underwood, Tusk had the resources and power to come in his way.
I think it could've easily been done in much, much less than 13 episodes.