So, of all the revisitings and reimaginings of Dungeons & Dragons before 2e (IOW, for most practical purposes, the OSR movement) what single rule change do you like or hate the most? If not a change, what addition? Hell, what omission?
For me, it was Lamentations of the Flame Princess removing To Hit bonus by level for everyone EXCEPT Fighters. It was such a simple change that fixed two long running problems:
1. Heavy armor stayed extremely valuable as you leveled up without the need of magic.
2. Fighters instantly became as valuable as other classes as you leveled up.
I think it was the simplicity with which those two old bugbears were slain that left the strong impression on me.
But nevermind what I thought. Sticking with OSR games, which changes did you love or loathe?