I only have two suggestions
Diversity:
Add MORE replayability to the game.. instead of a set amount of characters dying at point A.. make it so anyone in your group can die, maybe even set timelimits for certain areas. I know it might take alot of programming but it'll be worth it.. for example i'll use Season 1:
When in the Pharmacy, if you take too long to help with the door, Kenny can get picked off from outside, leaving you and your group to fight off the zombies and find another alt route out of the city.
Things like that.
suggestion two would have to be:
Bette relationships .. In Season 1, you could be a asshole as much as you wanted and Clemmy and Carley would still love you, how about if I be a asshole it effects my relationships more and effects my survival rate?.
One last suggestion
Character switch
I honestly thought this'd happen in episode 2, when you help Clemmy through the vent, I thought the game-play would switch to clemmy and you'd have to do a sneaking mission to get to the door, one wrong move and GAME OVER. I'd like to see this in season 2, to increase intensity (By making you play a part as a weak character or someone who cant defend themselves) In a very dangerous situation to assist your main character.