I don't see how Season 2 was better. 6 episodes of looking for a girl in the woods. A few episodes arguing on a farm. OMG, there's a zombie down the well! And then some genuine excitement in the last few episodes.
What genuine excitement happened in the 2nd half of season 3? They talked a lot about a war... I mean a LOT. And then the Guvnah ran away. There was no resolution to anything, really.
I thought Merle's final stand was genuinely exciting.
I'd say the last few episodes of Season 2 and the first few episodes of Season 3 are the shows strongest run. But as a whole, Season 3 was much more consistent than season 2. It had a run or two of some boring episodes and a disappointing finale, but even during the bad runs it hit back with a classic such as the episode featuring Morgan. There was never an extended stretch of monumental nothingness, like the majority of Season 2.
That being said, all three seasons are flawed to some extent.