I have played with several different crit rules and my favorite is that you always do max damage of a regular roll as the floor. Crit on a dagger with 20 Dex is 4+5=9, but you roll 2d4. If you roll below 9, it's 9, if you roll above 9, it's what you roll.

It seems like that would functionally be the same, but chunky grits make the battles in 5e even swingier. Still looking to play my first PF2E game to see how crits feel there.