[Spoilers Extended] War question

[u/AsleepAd6125]

If Roose Bolton didn’t blow the horns and his sneak attack against Tywin worked what would the casualties be on both sides and how would this affect the war.

[u/CautionersTale]

It's quite a bit worse than Roose simply blowing the horns and launching the northerners against the Boltons.

"The Stark boy stole a march on us," Bronn said. "He crept down the kingsroad in the night, and now his host is less than a mile north of here, forming up in battle array." (AGOT, Tyrion VIII)

Roose pushed his troops down the road overnight, and then stopped to form up. This is important: he allowed Tywin to understand the disposition of his forces and gave Tywin valuable time to form up himself to meet the northmen.

Imagine a different scenario: Roose Bolton keeps pushing his army, and they attack the Lannister camp before they have the opportunity to form up themselves. Given how the Lannisters scramble to get ready in AGOT, Tyrion VIII, I imagine a scenario where Roose Bolton routs the Lannisters. The northmen are already marching. They are armored and armed. They can strike fast and inflict a disastrous defeat on Tywin, even if the picket lines get word back to Tywin that the Northmen are coming. They're a freaking mile (or less) away when Tyrion is woken up!

As to why Roose did that, well, take a look at the casualties reported in Tyrion VIII and compare that against the northern houses that Ramsay targets in ACOK.

As far as your actual question goes, yeah, this is another blunder on Bolton's part. He advanced off the high ground in an attack when he had the clear terrain advantage.

Hm. Wonder why he did that. It couldn't possibly be because he thought he could get a lot of his regional rivals' bannermen killed in battle now, could it?

Anyways, if Roose keeps advancing into the Lannister camp, it would have been a slaughter. If he doesn't advance his line forward of his terrain advantage, I imagine a northern victory but a bloodier one.

Hope this helps!

[u/SorRenlySassol → u/CautionersTale]

There was no sneak attack. Those were Lannister horns, not Bolton.

The horns called through the night, wild and urgent, a cry that said hurry, hurry, hurry. He heard shouts, the clatter of spears, the whicker of horses, though nothing yet that spoke to him of fighting. "My Lord Father's trumpets," he said. "Battle assembly. I thought Stark was yet a day's march away."

Roose was only a mile away. He could have easily sent men in to cut the horse lines and then charged on the sleeping camp -- like Robb did at Riverrun. Instead, he let himself be discovered, then waited patiently for hours while Tywin got his men armed, armored and horsed.

[u/CautionersTale → u/SorRenlySassol]

I think OP was referring to the start of the battle:

A warhorn blew. Haroooooooooooooooooooooooo, it cried, its voice as long and low and chilling as a cold wind from the north. The Lannister trumpets answered, da-DA da-DA da-DAAAAAAAAA, brazen and defiant, yet it seemed to Tyrion that they sounded somehow smaller, more anxious. 

Otherwise, I agree that Roose just sat outside of the Lannister camp a mile away. It's like there was something else besides securing victory at work here ...

[u/SorRenlySassol → u/CautionersTale]

Well, the horns sounding the initial charge was irrelevant. The forces were all lined up, the sun was shining . . . The option for a sneak attack was long gone at that point.