Killing Beth was one of the first times The Walking Dead folks have gotten a little lazy and formulaic. Beth died pretty much just because it was the mid-season finale and they needed something big to happen. On the other hand, while I hate to see Tyrese go, this seems more like a natural part of the story of the group hitting its lowest point yet.
I actually think the last two half-seasons have been very impressive from a storytelling standpoint. They realized they couldn't really top The Governor saga and went out of their way to avoid repeating the Whedonesque "Big Bad" pattern. And after two very long story arcs, the farm and the prison, they really upped the pace.
I saw Michonne's frantic desire to get off the road in tonight's episode as sort of mirroring the creative staff's understanding that the show has to change and grow before it becomes a glossier version of Z-Nation.
Mike