During the sequence in which the dead are coming to life in the crypt, it can be seen that Tyrion's double is used in one shot, due to a bad wig.
During Jon's stand-off with undead Viserion, he avoids a burst of dragon fire by hiding behind a small rock. However, this would result in Jon's death, as Viserion's fire has been shown to be capable of burning through castle walls (and even through the Wall).
When the trenches are lighted all the white walkers are standing still next to the trenches for the fire to die down, that was a good enough time for the archers and Dragons to kill them with fire or dragon glass arrows. Why were they just waiting like fools.
Wildfire is never used or mentioned even though it would be an ideal weapon to use against an army who have fire as their Achilles Heel. Tyrion has used it successfully but the writers didn't even come up with an explanation for its absence.
It is said that white walkers can be destroyed by dragon glass or fire.
In the fight the white walkers are fought and killed with either fire or dragon glass weapons then how was the Night King able to raise them again (all of them).