1. get rid of subclasses, all subclass features are now feats to take, some might have a base class requirement, most would not have
2. weapon masteries are known, and can be applied to certain type of weapon attack, one per attack. not tied to specific weapon. we really do not need every rogue and their mother with shortsword+scimitar combo.
3. halfcasters have same spell level progression as full casters, but stop at 5th level and get less spell slots at earlier levels.
3a. delete 1/3rd casters, spell gain is just too slow.
4. getting rid of ability scores, use just modifiers.
5. weapons do fixed damage to save up on roll times.
beating AC by 5,10,15 or 20 points, deal extra 50%, 100%, 150% or 200% damage(round down)
missing AC by 5 or less deals 50% base damage and cannot trigger and on-hit riders.
Graze mastery would widen the 50% damage window to miss by 10 or less.
nat 20 gives extra +50% damage on top what you would make to keep the "nat 20" special.
I.E: great sword, 12 damage.
beat AC; 12 damage
beat AC by 5, 18 damage
beat AC by 10, 24 damage
beat AC by 15, 30 damage
beat AC by 20, 36 damage
if roll is "nat 20" add +6 damage
miss AC by 5 or less; 6 damage, cannot trigger on hit bonuses; adding poison, smite, sneak attack, masteries, maneuvers, etc.
other abilities:
Sneak attack, +2 damage per rogue level.
paladin smite: 10 damage for 1st level spell, +5 damage per spell level above
spell damage(not smite) is still chaotic and it's rolled.
6. saving throws removed, return to 4E where everything is an attack.
7. Short rest is SHORT!, one minute long. more or less you will have it after every battle, balance around that.
or removal of short rests completely.
8. healing made reliable, Cure, Healing word, restoration, Heal, combined into single spell combined into single spell.
Heal.
1st level spell.
Bonus action,
range 60ft
you heal target for 15 HP.
you can split the healing between target and yourself.
reduce healing by 25HP to remove Disease, Blinded, Deafened, Poisoned or Paralyzed condition from one target of the spell.
25HP per condition
upcasting:
+10 HP per spell level, +1 target withing 60ft per spell level, amount stays the same, you can just split the healing between more targets.
Life cleric: increase HP pool of Heal spell by +3HP per spell level.