I wonder why they have Desmond so drugged up. It can't simply be to transport him; a set of handcuffs and a gag would do the trick for that.
Aren't people usually drugged before they come to the island, as the trip is such a doozy? I remember Juliet going through the same thing during her flashbacks. I'm not sure what sort of timeframe we've had since Widmore's submarine came to the island a few episodes ago.
Anyway, really liked Jin and Sun's sideflash. During seasons 1-4 they were the emotional ground of the show, so it's nice to get back to that finally. I take it Sun would be pregnant with Jin's baby in this timeline? The two are a lot closer at this point in time compared to how they were in season one when the plane crashed.
It's a shame that the two will be kept apart for a few more episodes, but at least it's serving the plot. Their runion will have more resonance after last night's show. I'm guessing Sun's aphasia (seriously?) will go when they reunite.
I was very happy to see more Keamy, but Mikael was the icing on the cake.

I'm glad Desmond is back to play a part in the endgame. His surprise reveal at the end wasn't very surprising as his name has been in the credits all season. I'm just glad he wasn't forgotten about.
MIB needing all remaining candidates with him in order to leave the island clarifies his goals. Loved his meetup with Widmore, it was a great scene.