The mythology was fun in the beginning. But as it went on it became clear that there was no plan, they were just making it up as they went, and it got so disjointed that I lost interest. I still like the monster shows, and I'll take the lame mythology as long as they keep the monsters coming.
I'd say this season was worth it, more monsters than last time. Nothing that compares to "The Wear Monster" but still some good stuff. "Nothing Lasts Forever" had that creepy/disturbing vibe that reminded me of "Family". The AI episode was fun though totally implausible. The last episode was pretty lame I thought, especially if it's really the last one. But last episodes usually leave me cold anyway.