Who in that war room was a great general or tactician? Jon Snow has made tactical errors in every battle he’s been in, he’s not a tactician. Arya, Sansa, Danny and sam are useless. Jaime was a great fighter but not as a general, Brianne might have been the best at it and yet she never led an army.
Robb Stark was dead, Ned too. I don’t see why anyone would expect anything but errors considering who was left to make the decisions. I also don’t think anyone have the command for the Dothraki to charge in, they whooped themselves into a frenzy and took off.
Actual history is riddled w tactical errors by military leaders.