Themes
Bring back Themes as a extra choice at character creation. Grant bonuses/special abilities as you level up. Vastly increases the range of archetypes achievable without creating loads of base classes. If you want a warlord mix Tactician with Fighter, Paladin or Ranger. Mix Tactician with Rogue to get your burglar who plans the perfect heist. Eg
- Tactician - Help as a bonus action, use action to grant allies a move/attack as a reaction
- Leader - bard style inspiration, grant temporary hit point Inspiring Leader style
- Bounty Hunter - bonuses tracking/attacking marked quarry
- Ritualist - learn and cast ritual spells
Rituals
Separate Rituals from regular spells.
Make rituals skill based, use passive skill on lower level rituals (Unseen Servant - Arcana check determines how many servants you summon. Water Breathing - Nature check determines how many creatures you can affect).
Make more utility spells into rituals (Secret Chest) and more high level rituals.
Race/Ancestry
Ditch ability score bonuses and make special abilities highlight the differences. Eg half-orcs Relentless Endurance and Savage Attacks tell you they are strong and tough. Skill proficiency/feat tell you that humans are adaptable. Wood Elves Fleet of Foot and Mask of the Wild/Keen Senses tell you they are nimble and in tune with their surroundings.
You can tell a lot more about an ancestry by giving them a unique special ability than just a generic stat bump. Stops players feeling like they need to pick the "right" race to get a decent score in their main stat.