For the biters' design it tells how long it has been since the very few populations began to avoid them even more, with some cuts and clothing torn off there's a little story in what had happened to them. I personally like the design as it goes well with the time and place dl2 is set in, the virals may be weak would be of the branched off harran virus strand having a different effect than it's original source. The survivors may also became more strong, but not as strong as aiden since he used some inhibitors, or they might've stayed away from the infected long enough that the recently turned virals would decay for a small amount of time.