So my takeaways from that video (combined with my previous knowledge) was that the longbow is just generally the superior weapon over the crossbow. They have a far greater rate of fire and apparently greater penetration power. I knew that crossbows had greater draw weights and assumed that the would therefore also have greater penetration power. But according to the guys in the video the longbow is so much more efficient in transferring the draw weight onto the projectile that despite the difference in draw weight the longbow surprisingly also comes out on top in this comparison. You learn something new every day.
Key advantages for the crossbow were:
- Way less training required to operate it reasonably effective (could be represented in-game through the Crossow- class leveling up much faster, than the Longbow-class)
- In confined spaces a longbow quickly becomes impossible to use, whereas a crossbow can still be used without significant hindrance. In the video they specifically call out siege and naval warfare, but also mention how harshly only a few twigs overhead can impact the accuracy of the longbow
(Since you mentioned you are building a tactics game, maybe Longbow-characters take accuracy penalties or outright can't shoot while they are on tiles of a certain terrain, while Crossbow-characters are unaffected. This could create an interesting tension, if tiles of that terrain generally are desirable to be positioned in. For example the classic defense buff while standing in a forest.)
Also while typing this out I had a slightly different idea to implement the long loading times than just 'stunning' the unit after firing:
I'd give them a state like 'Weapons ready'. They can only use their crossbows while they have that state and once the do, they lose it. Later on they can spend their action on a 'Reload'-skill to regain that state. If you want to, maybe make it so that this skill can only be used if the unit didn't move, or didn't move far this turn.
While effectively still making it so that the unit can only fire every other turn, this would give the player more agency in when it is safe to 'take a turn off' to reload and when they'd rather retreat - or engage in close combat.
This I feel is less harsh, and therefore less of a nerf than 'stunning' the unit every time it shoots.