CleverNickName
Limit Break Dancing
Oh man, I'd make about a hundred changes. But for the sake of brevity in this thread, I'll just list my Top 3.By reading this thread, you are agreeing to an unbreakable NDA. If you admit to knowing this thread exists, I will know and come to your house and shave your eyebrows off.
So, WotC finally comes to their senses and asks you to be in charge of the new PHB, to go on sale in [REDACTED]. The new PHB should be compatible with the other non-PHB 5E books, but otherwise, you're free to go nuts.
What do you change? Do you eliminate darkvision for most races? Do you revamp the ranger and monk? Do you replace all the halfling art?
What do you do?
#3: Intelligence for Initiative and Ranged Attacks
I've always thought that Intelligence was more about quick thinking than quick reflexes. And aiming a projectile is just as much a mental exercise as a physical one...trajectory, drag, wind direction and speed, etc. So I would fix it so that Initiative and ranged attacks both use the character's Intelligence score instead of their Dexterity score.
#2: Condense the Classes and Subclasses
I would have only four classes: Cleric, Mage, Rogue, and Fighter. All others would be subclasses of these four classes...with a bit of overlap, depending on how you want your character to focus. For example, Barbarian and Monk would both be subclasses of Fighter. Paladin would be a subclass of either the Cleric or the Fighter, depending on whether or not you wanted your character to focus more on martial combat or healing magic.
The same thing for Subclasses. Eldritch Knight would be available for both Fighters and Mages, and Arcane Trickster would be available for both Mages and Rogues. This would let you decide if you wanted a full caster or half-caster version.
#1. Backgrounds Alone Determine ASIs
An elf who grew up in the city and spent 8 years at the Mage's Guild will have different strengths and weaknesses than his identical twin brother who grew up on a farm and spent 8 years breaking horses and hunting wildebeests. So all ability score increases will be determined by a character's Background, not their Ancestry and not their Class. If you have the Soldier background, you get a +2 to Strength and a +1 to Con. If you have the Adept background, you get a +2 to Intelligence and a +1 to Charisma. And so forth, for every background.
There are a number of other, smaller changes that I would make (I would eliminate darkvision for all races, I would enshrine spell points as the standard and bury "Vancian" magic in the DMG as an optional rule...) but these three are the ones I feel strongest about.