Only issue here is the suggestion that crossbows and normal bows require similar muscle strength to fire. The crossbow requires muscle strength to set the bolt, but firing is just pulling the mechanism. Crossbows were very accurate at short range and compared to training that a longbowmen had to undergo to utilize and maintain his/weapon crossbows were much easier to operate. Some career soldiers that operated the longbow show significant deformation of their shoulder/clavicle from extended use of the weapon. The crossbow removed the need for intense training to become an effective long-range soldier. The 15% accuracy makes sense in historical context, and bolts could punch through armor, but historically had a shorter range than bows, especially the longbow. As @hruza has stated, this is historically accurate.
The suggestion that they require the same muscle energy to fire is where I feel the urge to speak up. They also shined under different conditions and in that sense one was more powerful than the other under conditions suited to the weapon (longbow at extended ranges, crossbow in closer engagements). Even considering that, some bow designs allow for an extremely powerful shot at short range and the ability to puncture through armor as well. There is absolutely no way that all three (composite bow, longbow, crossbow) have the same velocity at the same points in their fire or have the same amount of power at the same point in their flight. Their “power” was not comparable, and definitely not the same.
And again this is not a history sim. I highly doubt all of the weapons abstracted into the game were at use during the same period in history. Anachronism is part and parcel to the fantasy genre as bits are often taken from varying parts of history, and often certain weapons and customs simply did not exist outside of a very specific context. The knight would not exist without the creation of the stirrup, which took place in the steppe’s farther east than the source material for this game. In short, no geographical equivalent to the steppes = no stirrups = no knights. It doesn’t stop there. No equivalent to ancient China & Korea + no avenue of trade and commerce to spread it = no crossbow. Beyond that, it’s anyone’s guess how technology and armor design would have changed if humans found themselves sharing the world with dangers like the ones in BB. Considering that armor changed with the time to adapt to different challenges, they would absolutely not look like the pieces in game, since those items look like items directly from our world. Different weapons were similarly adapted to contend with challenges presented by armor and other conditions. Games like this fall apart when subjected to that sort of historical scrutiny.
This game is fantasy, and is enjoyable as fantasy. It is also meant to be enjoyed as a game. Balance issues should not be sacrificed for a historical accuracy that could not exist given the context.