I have to say, I notice a common thread between people who tend to complain and complain and complain about Game of Thrones.
The people who complain tend to say things like:
"This episode didn't do enough to advance the plot" and "Why are these characters taking up so much precious screen time? We only get 10 hours a year so I'd rather see other characters!"
You have to accept that you get a little less than 10 hours of screen time per season. If you spend half that time worrying about all the time "wasted" with the characters that aren't your personal favorites, you're going to have a bad time.
No, the show can't just stay with Tyrion and Arya the whole time, as much as you would like that. The books are simply not written this way.
So if you have no interest in Jon Snow and the Night's Watch... well, if you didn't want an entire episode devoted to this plot, then you would have needed more of this plot spread throughout the season. Personally, I think it worked better this way.
I thought this episode was riveting. The action was infinitely better than that of every summer blockbuster you see in theaters these days, because unlike those crap movies, you knew that every character actually faced the possibility of death. That makes the stakes huge, compared to a superhero movie in which the stakes are almost non-existent, because the outcome is a foregone conclusion.
Also, to anyone who says "Jon has plot armor" and "Sam has plot armor", and that it's "sooo obvious they can't die."
I call bullshit. These are the same people who said "it was so obvious that Oberyn was going to die, GRRM always kills the good characters!" You can't rationally tell me that you knew Oberyn was going to die and that you knew Jon and Sam were going to live. Even if you suspected that might the the case, there was still enough doubt that it's not something you could take for granted.
Overall, I really enjoyed the episode and I can't wait for the finale. And I feel bad for the people who only want to criticize and nitpick this show to hell in between the Tyrion and Arya scenes that they're waiting for.