The importance of getting it right
By now most people who care have probably seen the most recent episode of Game of Thrones (Episode 3 of the final series, for any internet archaeologists out there). Those who have not might want to avoid this little rant for now since there may be the odd minor spoiler in here, though I'll resist any blow-by-blows or casualty lists.
Anyway, those of us who have basically any understanding of tactics were probably more than a little perplexed by the way the big battle in this episode played out from a strategic point of view. There have been quite a few very detailed breakdowns elsewhere by people better qualified than I, but it doesn't take Sun Tzu to spot that the cavalry and artillery in particular were spectacularly mishandled. I've seen a few comments expressed to the effect of this not mattering, or things like 'I must have missed the bit in The Art of War about fighting zombies with dragons', as one particular God of Snark put it. As you might expect, I disagree pretty strongly.
Here's the thing- if your heroes are meant to be everyday men in the street, there's no problem with them doing dumb things on occasion. It always annoys me when critics whine about dialogue in movies or books where people respond to stressful situations by shouting 'F*@k you!' because they say it's 'cliched' or uninspired when the reality is that real people don't always come up with the best and most poetic lines on the spot. But if your heroes are meant to be experienced military commanders (and in the case of GoT, they had enough veteran warriors and strategists to run three campaigns at once) it's important that they at least give some impression of being just that.
In part this is that old classic 'show, don't tell'. You can tell us Sir Hack of Slash is a military genius, or you can show him pulling off a brilliant tactic against impossible odds and make us believe it. Better yet, do both. In the specific case of GoT, it's entirely fair to say that given that their enemy had effectively unlimited numbers and could raise the dead to fight again, no strategy the defenders might have employed would have made much difference, but that isn't really the point. Had we seen the defence well-planned, with a properly obstructed killing-zone, the artillery pounding a hampered advance, archers killing hundreds of the enemy whilst they were held up in the field, etc, it makes the true scale of the threat that much more impressive when they take all of that and just keep coming. As it was, we're left with the impression, false though it may be, that the various heroic sacrifices might have been completely unnecessary.
We see this in a lot of games and movies. One of the Dragon Age expansions, for example, tasks you with defending a castle against Darkspawn, and at one point presents you with the 'choice' of sending troops out to defend farmers in their fields (weakening the castle's defences), or leaving them to die. Of course, anyone who knows the first thing about castles and the feudal system knows that the whole point of the damn things is to bring the food and the peasantry inside at the first sign of trouble, which makes the whole 'choice' feel cheap and the inevitable NPC harangue you have to endure whatever decision you make feel undeserved.
Likewise, in some 40k novels and shorts we see troops fighting using tactics that make no sense whatsoever. Quite some time ago I reviewed the short story 'Mercy' by Danie Ware and whilst I actually quite like that author from what I've seen I stand by my main criticism of it, which is that the tactics employed (and their result) don't make sense. If you write a story where a Guard commander has been reading too much Regimental Standard and orders his men to engage Orks or Genestealers in melee with bayonets rather than 'waste' ammunition on them, that had better not work or all you've done is make the enemy look like a joke. Even if it fails, you've opened the door to the idea that defeat would have been avoided with a competent commander, which is fine if that's what you're going for, but a big problem if he was supposed to be highly-skilled. Losing against impossible odds is fine and can be heroic, but it doesn't look that way if you make the enemy's job easier for them. Death is acceptable, failure is not, to use the old Imperial adage.
As a counterpoint, we could think about some of the great desperate defences of history, like Rourke's Drift, The Alamo, the Knights of St John in Malta or Stalingrad in WWII. Whilst adaptations of most of those exist, to varying degrees of success (both on the part of the adaptation, and of the defence) one thing they have in common is that most of the best at least pay lip-service to getting the facts straight where possible. At some, like Stalingrad, both sides made horrendous mistakes at various times and trying to gloss over that seriously distorts the narrative. (As an aside, the directors of GoT could have done a lot worse than watching Zulu for some ideas!) In fantasy, we could look at the defences of Minas Tirith and Helms Deep in LoTR, which to my mind did a far better job of showing a defence that failed (or could have) not because of incompetence or cowardice, but due to the sheer numerical advantage of the enemy.*
So anyway, that's my hot take. Consistency and accuracy matter, not because of the need to ablate torrents of potential nerd-rage** but because if you don't have them, it begins to cheapen your story and weaken any sense of peril or threat, a trap more than one otherwise good author has fallen into.*** Of course, we should be careful not to lay too much of this on the shoulders of GRRM, since his story will presumably work out a little differently.****
Oh, and 'they' were still bad-ass. You know who I mean.
*And in at least one incident, their flat refusal to die when pin-cushioned with arrows. Torch Ork can serve in my Waaagh any time.
**Because as I've said before, once a certain crowd decides they don't like you there's literally nothing you can do to change that...
*** Cough-The Belgariad-Cough. I'm not kidding, I do have a cough.
****If the stubborn bugger survives long enough to finish it.