RPGMemes

Two big things I love:

• Three action system: every "activity" (strike, stride, cast a spell, etc) has an action cost. On a standard turn, your character gets 3 actions to spend on those various activities. This obviates the need for DnD's rules about spending a whole turn running since you can just spend multiple actions striding.

• Keyword system: PF2e leans more onto standardized keywords and uses them appropriately. Everything (all actions, weapons, items, even statuses) has a set of traits that (usually) briefly explains how the thing acts. It allows for standardized templates for interactions between different elements of the game. This takes a HUGE burden off the GM during game play, esp for modules that weren't written to think about each other. All the examples I can think of would take several pages to explain, but you can look up some things on Easy Tools and see their traits.

Bonus thing I love: all the rules are openly published, leading to TONS of extra tools that just make the game easier to run. (That said you should buy a set of books to help the publishers after you've been converted).