The mission was not a good idea and it seemed they only had one or two Valerian steel weapons?
And they said Jorah was the one who finished the bear with a dragon glass weapon of some kind.
Why didn't they all have dragon glass weapons?
They could have also took a cage of ravens along with them so that Gendry wouldn't have to run back, though it was probably good that he didn't get stranded with the rest of them.
The Night King could have just killed Drogon, the dragon that was on the ground with Dany and the others. Kill Drogon and the passengers are dead. Killing Dany would have been a huge coup there. Instead he aims for one in the air, going for the degree of difficulty on the javelin toss.
It looked cool to see the mortally wounded dragon glide down to crash into the frozen lake, with a trail of blood but would they come down like an airliner or just tumble and drop to the earth? If that dragon died from the ice lance strike, would it be able to keep its wings rigid and extended?
I watched the after show segment with the show runners and they said if the NK couldn't kill one of the dragons and turn it into a zombie one, the clash between the humans and the dead forces would not be much of a contest. So to keep the suspense for next season, the sides had to be equalized somewhat.
It would have been cooler and more frightening if the NK just raised the dead dragon and it sprung out of the frozen lake into the air and then the camera zoomed into the blue eye. The zombies pulling it out of the lake with the chains gave away what was going to happen.