Man in the Funny Hat
Hero
Alignment is certainly an area where the original concept has changed a lot since its inception, and for the better. XP penalties for alignment violations was something I just could never swallow. I understood that was how it was MEANT, but just not something I could bring myself to inflict. Actually, I found level drain to be similarly inexplicable and inexcusable as far as penalizing PC's experience points with the effect. Again, that would be because if it was supposed to be a player participation control mechanic how has a player offended to the point of deserving the PUNISHMENT of lost xp for his character?I also see it in 1e terms but I long ago intentionally chose to ignore the player-control mechanisms suggested by EGG. Ditto for alignment change; alignment in my game is much less hard-and-fast than original 1e would have it.
The things that xp has been used for, how and why they are awarded (or penalized), has changed with each edition as RPG "rules theory" has itself changed. Sometimes for the better sometimes not. I began to seriously question its uses and abuses in the 2E era. In 3E I came to see it as primarily a tool for control of the pacing of advancement (which everybody ignored). I've actually handled it a lot of different ways even within the same edition, even within the same CAMPAIGN.To me, XP are a character reward; and while players enjoy seeing their characters get 'em I very much try not to use them specifically as a player reward.