Last night's episode really annoyed me. I spent all day Saturday "wargaming" a tactical plan then I watched this poorly executed deliberate defense. So I was in analytical mode.
If you have obstacles (trenches, tricalps etc) they are used to slow or divert the enemy. If you have fire support (cannons, rockets, missiles) you target the enemy at those points. Also calvary doesn't attack head on, usually used along the flanks.
So if I'm defending Winterfell, I have flame trenches and dragon glass tricalps emplaced at near the limit of trebuchet range. I add another line of them at the limit of long bow range. This provides targets for the indirect fire weapons. Then I would have flaming oil ready to poor on those who make it to scale the wall. I would also continue to use dragon fire on the enemy at the choke points.
I keep the Dothraki cavalry on the flank to quickly maneuver to engage the enemy on the flanks and keep them cannalized.
And that's just my issues with the tactics. The long stares the running from 4 dudes in the library after you dropped about 88 in 2 seconds was just meh. Also I want to be up there fighting. Chance to fight comes. Nah I'll just chill here with my Valarian steel dagger. The long leisurely walk to Bran and smug face.