I thought Episode 2 only wasn't a clear weak link because the whole season was pretty average, but I'm willing to admit I may be in a clear minority. I'm not sure what general vibe they were going for, but it came across as "Over-produced sitcom with a little bit of mystery." I would propose that through nine episodes, "A Study in Pink" remains the high-water mark for the series.
I felt this season had a lot more to do with letting us enjoy the dynamics of the relationship(s) as they had developed in the first two seasons than pushing the crime/solving aspects in any significant way. That lends to the sitcom style that CW mentions, but I didn't mind. I would have liked Mary's background to have been threaded over the three episodes versus dumped on us (and then dumped all together) at the end. I'm hoping that it will allow her to be a more active agent in the crime solving bits going forward. Finally, while I liked the Moriarty arc of last season, I'm not thrilled by the end of this season and what it means for the next. I think I liked the "Elementary" take on Moriarty more than the "Sherlock." Or it's possible that I just get annoyed with Andrew Scott's voice when he is over-mugging as Moriarty, which is most of the time.
Nah, I thought this season was just okay. Better than most TV, but a fair bit under the past two seasons. Despite this season's lackings, Freeman was uniformly excellent.
I'm only through The Sign of Three (second ep), but I generally agree that there's much more focus on humor this season (sorry, not using "series"). I found the first two episodes deliriously confident, which was a treat, even if it came at the expense of more serious aspects of the show thus far. (For example, I found both Sherlock's waltz through the restaurant in "The Empty Hearse" and the "hungover Sherlock evaluates the crime scene" bit in "The Sign of Three" were just brilliant.) I will say that I always wonder whether the show's confidence and competence obscures an underlying streak of nonsense. That is, I'm not sure the plots would make as much sense a second time through. To take an example from "The Sign of Three," I wondered why the killer would have stalked Bainbridge (which is what led Bainbridge to seek Holmes's assistance) before the killing. Given what we learned about why Bainbridge was killed, couldn't Small have just watched the Beefeaters generally, and then gone after whichever one he wanted? (I'm sure we can all come up with hypotheses as to why he would have watched one in particular -- I'm just not sure I really buy them.)