The only problem is that 10-15 pierce damage would not even penetrate medium armor. Although archers use low damage bows, their Power Draw boosts the damage they do. It would need to be 25-30 pierce minimum to be effective on the battlefield.
This was actually how they were in real life too, anything heavier than cloth was fairly well protected against them. These were only ever used firing down on attackers for maximum effect, unloading 10 bolts in quick succession would probably not kill the victim, they would more likely be only lightly wounded at best as most of the bolts were deflected but their force was instead intended to pin someone in place for a while so that other ranged might make the kill.
If anything they should have damage on the lower end of that range, like 12 so that they can still affect people in the upper end of light armors but for medium armor only the stun would be a factor when facing them. Chain and above should be all but immune to them and plate in any form wouldn't even be stunned a little.
They should be very inaccurate, slow to reload and more of a support weapon really. This could make melee crossbower a thing, I can see this being used to shoot someone at point blank 10 times while the friendly melee just brutalize them. Make them very heavy too then, so that the melee can still catch them when this happens.
Doesn't this seem an interesting enough playstyle to be worth a test? Support Ranged.
If it totally breaks the game can't we just remove them as well? As this bow has been suggested now many times and is always turned down
.