This is just my opinion, I’m not an expert either, but…
I’m noticing a lot of, shall we say, “tacti-cool” in that video. If this “holding all your arrows in your draw hand” is the most accurate and powerful way to shoot, why don’t Olympic archers do it? This guy seems to be shooting around 10-20m, while Olympic range is more like 70m.
He also clearly isn’t using a very high poundage bow, or he couldn’t draw it nearly that fast. In fact, I don’t think he even pulls to full draw. Looks like just a few inches most of the time. He seems to be using some sort of traditional recurve(ish) thing, nothing like modern high-power compounds, which is what hunters (whose primary concern is to kill a thing) use. I’ve had that discussion plenty, 2000 year old reflex bows simply cannot compare to a modern compound bow in terms of power.
He seems to be basing everything off of Eastern bows and methods, which isn’t necessarily wrong, but it’s a different beast to English/European bows and tactics. If you have 200 archers then you don’t need speed, accuracy at range is far more important in a large-scale battle, and you certainly don’t want to be flailing arrows around the whole time. If you can be accurate at long range, then your speed probably doesn’t matter.
He still stands still and takes his time when he shoots a long distance, and they did say he’s been doing this for years, so it’s not something you’d just pick up ingame, although that could be said for all the martial arts ingame.
Archery skill should definitely increase reload speed, that’s just a given.
An arrow rest is going to give you better power and accuracy, that’s a fact, at least with a fletched arrow. Drawing on the side of a long/short/reflex bow is a given, but it shouldn’t matter much which side you draw on and I certainly wouldn’t with a modern bow. Also, your palms are in the same position regardless of where the arrow rests, so it’s just going to come down to what you’re used to. Modern archers draw on the left because that way you can use a sight on the bow, which makes a huge difference at long range.
As an ingame martial art from a book… it could be interesting? A sort of Bow-Fu? Perhaps it cuts your accuracy substantially in exchange for faster firing? I don’t know if it would be useful or possible to implement, but it’s an interesting idea.
“Who can escape 10 arrows, fired quickly after another?” Well, you don’t need to if you run up and stab the guy. Or have a shield.
The best I can offer is a reality check: If this was the best way of shooting, why does nobody shoot like that anymore?