The Mongols would disagree with you that its hard to shoot a moving target with pre-gunpowder weapons.
Not really. As skirmishers, the Mongols would force an enemy to set their position to fight back. This let the Mongols ride past at range firing volleys until the enemy broke or was severely reduced. This is why the typical Mongol horse archer carried a complement of 60-90 arrows. Then they'd ride past at very close range for aimed shots. For fleeing targets, they'd use their horses to match direction and velocity, reducing the relative movement as much as possible before firing. A target moving across their engagement range would still be extremely hard to hit.
Mongols were very good at firing while moving, but they had the same issues as everyone else at hitting moving targets.
Crossbows are ridiculously easy to fire at moving targets.
Sure, so are arrows, slings, rocks, fireworks, rubber bands, and Nerf guns. It's the hitting that's still really hard.
Let's all agree that a modern military issue firearm is superior in all ways to a crossbow. That stipulated, the best method to avoid being hit aside from full cover is to move, at speed, laterally to the shooter, varying your step as unpredictably as possible. Why is that? Because hitting a moving target is hard.
You can definitely swing more times with a melee weapon. It can also be dodge, parried, blocked or absorbed much easier than a ranged shot.
Well, no. Just because there are more words to describe defeating a melee attack (parried isn't often used for defeating a ranged attack) doesn't mean it's easier. Heavy armor was proof against most ranged attacks, up to and including ball musket firearms (read up on late plate armor still being highly effective defensively even after units of musketeers were in common usage). With arrows and other muscle powered weapons, armor was fantastic. It's why, historically, you didn't commit your archers at heavy infantry or cavalry but instead at skirmishers or light infantry. And even light infantry was a hard target for archers if they could raise shields.
Missile fire wasn't a huge component of medieval and ancient warfare because, at the end of the day, it was the heavy infantry that ruled the day. This changed only once manufacturing processes became capable of creating ranged weapons that weren't strength powered. Even the famed English longbow only had a brief window of importance before being replaced with cranked crossbows and firearms. The necessary strength and training to operate the massive yew longbow wasn't sustainable (and archers had short service careers and generally crippling complications from being archers). The advent of non-strength powered missile weapons allowed for untrained massed fire that could punch through light and medium armors. As a force multiplier, it was fantastic. But, even then, melee troops were still the ruler of the battlefield until firearms became so ubiquitous that all troops could be issued a firearm that doubled as a melee weapon (the reason bayonets and bayonet drills were a core part of all military training through WWI). You'd shoot, reload, shoot, and, if the enemy advance wasn't broken, then it was into melee. Cannon was really the death of melee troops on the battlefield, not personal ranged weaponry.
Even today, ranged accuracy on the battlefield is shockingly low.
Melee attacks should not have additional effects besides damage unless it is due to a magical effect. Most monsters are melee based as has been pointed out in various posts in this thread. If you assign PC damage and effects you have to add it to the monsters and they have to be FAR more devastating! A giant striking you with his great sword or a gargantuan red dragon biting you would cause horrific damage. There is a reason that most monsters do not have an rider on their damage because it is not needed and would make combats too deadly.
And these are very valid
game points -- we're playing a game that should be fun, not recreating historically accurate warfare, which is very much not fun. The key here is that the game only loosely adopts the forms of historical combat tropes, it doesn't mimic them. Real world missile weapons were hard to employ effectively across the vast majority of the history of warfare.