Strategy 101.
This show is will go down in history as the one with all the stupidest and worst military strategies.
Again, an defending army waits outside a castle instead of behind the walls.
Euron's fleet killed a Dragon and over a dozen ship last episode and now they couldn't even stop a few ships from landing soldiers by the capital's wall?
Why didn't Dany use the cover of night to deal with Euron's fleet before the battle? That would have been a great scene and made the whole "suddenly invincible Dragon" more believable for the rest of the battle. One could have argued that the Ironborn were great shots while Lannister manning the scorpions on the walls were not.