Dante
Average bang
It wasn't 4. It was about 20 or 30, and that's just what was visible on the screen.They fired like 4 shots in to the back of the Wight lines, what a barrage.
The dothraki charged head on with light cavalry in to a packed infantry army, with zero disruption coming to the front of the wight lines beforehand. They couldn't outflank the wights
It made sense to nobody with a hint of military experience ever. Literally as soon as I saw them charge I laughed because it was that stupid. Light cavalry charge in to an abyss unsupported by archers or infantry against an enemy who can turn your dead bodies in to their own soldiers, gg.
Again, the Mongols used lances specifically designed to break infantry formations, rained arrows down on the enemy formations to disrupt them, but most importantly they were the best co-ordinated army of the Medieval era. No Mongol army would ever charge in to an abyss with no scouting or clue about the enemy because they were tactically superb.
The dothraki should have either a) simply accepted that a cavalry force in this scenario (siege defence) is tactically foolish and abandoned the horses. They're superb fighters on foot as well and 100,000 extra troops guarding the walls (which had nearly nobody actually on them) or the gates would have been priceless. They're portrayed as skilled archers, get a line of them on the walls.
Or b) found space on the flanks to attack the rear of the wights whilst the unsullied held the line. This is hard because visibility is basically zero and the wight army is humongous, you're not going to be able to co-ordinate any flanking manoeuvres.
The worst thing they could possibly do is abandon the main army and go on a suicide charge well ahead of everything for no other justifiable reason other than 'well dats wat da dothraki do init' as if that somehow justifies throwing away 100 thousand of your best troops.
The barrage happened before the Dothraki met the Army of the dead.
Here's a decent write-up of the impossible situation faced by the Army of the Living:
https://slate.com/culture/2019/04/battle-winterfell-military-analysis-tactics.html
None of this makes the cavalry charge a good idea. But the mistake was made in the days before the Battle of Winterfell, not in the minutes before the charge. The best employment of the Dothraki would have come as long range scouts and skirmishers in the days before the battle. Even then, however, their utility was limited; cavalry often succeeds by disrupting supply lines and ambushing foraging parties, and Team Dead needed neither of these. And in any case, unless Team Alive spared a dragon for air support, any accumulation of Dothraki would have been vulnerable to Viserion. If the Dothraki had not charged, they would have found themselves pinned against the infantry, their mobility lost. If they had moved right or left in search of Team Dead’s flanks, they would have run the risk of being flanked themselves (Team Dead also had cavalry, and its infantry was fast and fearless) or destroyed by Viserion and the Night King.
They were always going to lose. It's much more obvious in hindsight, but an overconfident Dothraki hoarde is in keeping with their characterisations up until this point.
Maybe you're coming at this from the point-of-view of a book reader. But as a show-only watcher, everything I'd seen up until this point gave the impression of the Dothraki as almost invincible.