Verisimilitude and the Art of the Crossbow Expert!
I was never a fan of the Crossbow Expert feat as it didn't make sense that you could load and shoot a heavy crossbow twice (or eight times if you were an Action Surging 20th level Fighter) in six seconds. Whenever I voiced this complaint inevitably someone would say, "But Fireball!" as if all that was required for a Wizard to create a 40' ball of fire was to "wiggle his fingers with a pinch of bat guano and say a few words."
No. It takes more than that. A Wizard uses magic to make a Fireball. Magic is the science of D&D. It would be like saying that you wanted to throw a bullet at someone without a rifle and it should be just as effective. Likewise, a Monk can punch a dragon to death because of magic, not just because he can punch good.
I considered just banning Crossbow Expert as a feat, but I know people like using crossbows and the character fighting with two hand crossbows is a cool concept. So, I applied science (read: magic) to the Crossbow Expert feat. I see it as similar to the way that Fey Touched, Shadow Touched, Telekinetic and Telepathic feats give you magical abilities.
Crossbow Expert
General Feat (Prerequisite: Level 4+, Dexterity 13+)
You gain the following benefits.
Ability Score Increase. Increase your Dexterity score by 1, to a maximum of 20.
Magical Loading. You may perform a 10 minute ritual to enchant a Hand Crossbow, Heavy Crossbow, or Light Crossbow. Thereafter you can ignore the Loading property of the enchanted crossbow. When you make an attack with one of your enchanted crossbows, it will magically cock and load a piece of ammunition you possess in a quiver that you have equipped without the need of a free hand.
You can have up to two enchanted crossbows. If you attempt to enchant a third crossbow, you must break the enchantment with one of your existing enchanted crossbows.
Firing in Melee. Being within 5 feet of an enemy doesn’t impose Disadvantage on your attack rolls with crossbows.
Dual Crossbow Wielding. When you make the extra attack of the Light property, you can add your ability modifier to the damage of the extra attack if that attack is with a crossbow that has the Light property and you aren’t already adding that modifier to the damage.