When the new writers took over, they really struggled to keep the characters in character. They had people doing things that just weren't things that those characters would normally do.
But this past year, they really brought it back. It centered around the campaing to be Bartlett's successor in the White House, focusing mostly on who would win the Democratic nomination. The season finale ended with the nominee being named, and next year will basically be centered on the race to the white house.
West Wing is probably my favorite show ever, and believe me, nobody could be much more disappointed with the first season post-Sorkin than I was. But it's definitely worth giving it another shot.