Every location drags out in a TV series like this. They have a budget, and it's an expensive show. Not too many TV shows have to provide 50 undead people per episode.
The current goings-on are perfect for the prison set, the lighting, the sick people in lockdown, the gloom...yeah they will be leaving eventually but gee whiz do people think they are just going to pack up and leave without any place to go to?
I know that all TV shows have people that feel the need to cut the legs out from under them, but really - killing off main characters "just to make it interesting" is absurd. There are some senseless deaths for sure but usually there are good reasons to kill off characters - TDog being a great example. I loved his character and wanted to see it expanded and was shocked when he got it, but Tyreese was coming along to be a new badaZz guy and he did die a real hero saving Carol and all.
The show is handling a lot of character arcs at the same time in a pretty well constructed way, the action scenes are still bringing it, and the character interactions are all either directly relevant or at least interesting to see where they go.
That psycho little girl for example, that almost inconsequential subplot has tons of potential for crazy things to happen. Herschel has been absolutely amazing too. Last nights episode had me feeling that it was the lowest point for the group...again. And that's pretty great.