I'm slowly working my way through Season 2 right now, and while I haven't noticed any significant drop in the overall quality of the series relative to Season 1, I am finding myself disappointed in the way the season marginalizes the Horseman of Death, especially since it also relies heavily on John Noble's Horseman of War, whom I just can't stand (even though I'm generally a fan of Noble as an actor).
Thankfully the individual stories being told episode-to-episode are interesting and engaging enough to offset my complaints.