I thought the series started well, but the prolonged stay in the Prison really stagnated it.
As for characters, they need to learn from Game of Thrones - kill those that you least want dead.
The ones I started off disliking - Carol, Daryl, Michonne and Beth - are now the ones I'm rooting for. And Maggie, purely for asthetics, but I am willing to trade her for Rosita.
As for the season finale... I'm just glad they're (shhhhhh!).