Mega bump to finally comment on these series, now that I've catched up.
First two seasons were good, if the series would have ended after Season 2 with Frank knocing on the Oval Office's desk it would have been a fitting closure.
Third season was kinda meh, but fourth season was a marked and evident improvement. Especially the final episode was breathtaking, it was almost like a thriller movie.
I agree with the last comment made in this thread - the annoying problem with a show based on a bad guy like House of Cards is that the bad guy always has to win. He meet strong adversaries, and then they all melt away like nothing. Cathy Durant was a real problem, and then all it took was a "I kill people! ahahahaha no, I don't, but I would have. Do what I say" moment to turn her around.
The scene was acted brilliantly by Kevin Spacey, just like everything he does, but the plot was weak.
Anyway, since this show already takes a lot of liberties and is not interested in being realistic... how un-realistic will it get for you in future seasons? will Frank become a dictator postponing or suspending the election, and actually keeping power for himself? story-wise he will be re-elected, it's hard to imagine the show going on with him no longer in the White House.