I really liked this episode.
Yes the dialog part with the O6 Locke met were "low action" scenes. That doesn't make them bad.
Some people noticed that he doesn't mention his new name to all the people. Well not mentioning on screen, doesn't mean not mentioning at all. Also goes for the other things that they say are missed. Or the questions NOT asked by O6. Maybe they did ask them. Esp. for Jack, Jack knows the new ID of Locke since Locke was submitted to the hospital with his new papers.
We do learn things, even from the little dialogs he has with the O6 people. Esp. Michael's son, I find his reaction pretty normal. Remember, he went through A LOT plus he is one of the "special" people (so he might already know more than meets the eye). I am not sure if this role is faded out just yet.
As for Lockes old love. She could be dead or not. We cannot be sure. Even if she was alive, people that try to guide Locke to do what he is supposed to, can easily fake a tombstone (they can do more than that - even THEM killing here for real). So no problems in the plot there either.
I am not convinced on which of the two "war fronts" (as seems clear now) is good and which is bad. If you ask me, possibly both are bad and we need to get a good one from our original Lost team (Locke, or even Jack) to be the next to take over and clean all the mess.
I cannot forget what Widmore did when he first met Desmond, or his 17 years old character, or the camera where he hit a guy with his bare hands. Not a "good person" by standard measures (but what is standard in Lost?).
Ben could know that Locke is gonna return from the dead, but on the other hand, he says "I'll miss you" so maybe not.
Maybe everybody is a pawn for the guy in the cabin. ;)
Talking about Ben, I am not sure why people find it strange that he first saved Locke then killed him. It's BEN people! He heard what he wanted to hear (I don't say "expected" or "not expected", that remains to be seen), then put things back on track.
Abbadon dead. Interesting. This doesn't mean it's the last we see of him. I am not saying the (now usual) resurrection but he was much involved in people's "past", let's not forget.
The... bravest thing of all though, was for the writers to keep the NEW flight people (not just the O6 and the two new guys, but the whole flight) in the show. Brave. ONE MORE Losties team, with all the implications this could have. I wonder where Lapidus went. I never expected he would crash the plane, it was clear from what he did with the helicopter too ("what? crash it? I didn't say I crashed it"). After all the plane was just struck by the inter-dimensional movement, not by electromagnetic forces that Desmond crashed the original 815.
The two new guys (what's the name of the male? Ceasar?), I am not sure if they are ok. Certainly look like Widmore personnel. We'll see.
People saying "nothing happened" or "filler"... erm... did you really see the episode?