I know a lot happened in Season 1. That's not the reason why I think it's weak, I just felt that a lot of exposition was fitted in in a very clunky manner. The show is much more sophisticated at it now.
Also, the same number of events you listed for season 2 can be listed for season 5. Stannis prepares for a fight with Roose Bolton. Barristan ends up dead, with Danaerys having a long awaited interaction with a major character. Jorah contacts Greyscale, Jon is made Lord Commander, executes a prior Lord, then starts a rift between the Night's Watchmen and himself by siding with the wildlings. Also, a very important decision is that the wildlings are finally going to be shifted south of the wall. Things are building up to a head in Winterfell with the Boltons, Stannis, Brienne, Sansa and Littlefinger all headed to the same location. Cersei, Margaery and Loras are all imprisoned by the high sparrow. Really, a lot has happened this season; it's just that there hasn't been any one outright brilliant, which will probably come in spades from next episode onwards. Also, it's worth remembering that Season 3 also really only had three really good episodes until episode 8 of the season (and it even had a very sub-par finale). This season has also had three great ones (Kill the Boy, High Sparrow, and The Gift), and will likely have a spectacular finale from the way they are hyping it up.