I thought BYUJacob's thoughts were very interesting and well considered, but I had essentially the opposite reaction. Season 2 was a bit of a letdown for me because it felt like Underwood went from victory at the end of the first season (VP) to victory at the end of the second season with only token resistance. It felt like every other character was essentially stumbling around in the dark and there was never any real threat to Underwood. Will him becoming president at the end, I was basically ready to give up on the series totally. I'm just not interested in watching a basically all-powerful character face no real challenges.

This season essentially redeemed the series for me (still not as good as season 1). Underwood faces real challenges from competent opponents and it's not clear he can just easily overcome them. Even his victories come with a cost, which is right in my wheelhouse.

Your mileage may vary, depending on what you like about the series to begin with. If Season 2 was great for you, Season 3 will probably not be what you like.