Pretty much everyone is out of character, it's unusually episodic, and the stories are just dull. Thankfully, the election storyline in the final two seasons gave the show some much needed direction and I think the show ended on a high.
That's how I feel, there are some OK stories in season 5, like the Supreme Court nomination episode, but you just can't enjoy it to the fullest because they characters were such asshole and out of place.
The best thing they did was skip a year and go to the election. I wish they planned it better so the year didn't just disappear, but most people don't notice that.