Now, about pure good and evil, honestly, it's never been that hard, especially considering that alignement has always been fuzzy guidelines, non-prescriptive and descriptive only, and that people have never been expected to be absolutely consistent with their alignment, except possibly the paladin in 1e, hence my reference to Galahad. But note that, even then, a paladin was alway free to commit an evil act, it was not prescriptive. What it did, however, is record what had been done and there were consequences, as is normal with all acts, although quite drastic in the case of a paladin.
Yes, and that's why alignment works for me as fuzzy guidelines that everyone has room to interpret for themselves but not as a top-down DM-controlled god or force imposing their own interpretations on the players.
For paladins, I prefer for their restrictions to be based more on their oath -- which may be related to alignment or it might not, but either way I would expect that to be a conversation between player and DM. Which again goes back to players having space to interpret the alignments for themselves and work out with the DM where the lines are on that interpretation.
My table is made up of a diverse group who aren't all from the same country or religious background. They like exploring issues of morality in the game. They
don't like having heavily culturally Christian-leaning ideas of good and evil pushed on them, particularly if it's something that they, as players, don't have space to push back at.
As for the definitions, you can use what works in your game, but good is simply caring about the welfare of others, possibly above yours, and evil is about not caring at all or even purposefully hurting others.
I recently played with someone who played a traditional paladin -- roamed around questing to help people, prayed to his god every morning, proselytized to everyone who would listen. But we were playing in a setting that was hostile to adventurers because they have historically entered the area simply to loot it and destroyed the ecosystem on the way. The paladin constantly refused to understand this perspective and happily talked about taking loot and killing local fauna right in front of my character, the local guide who had reluctantly agreed to help the party despite said hostility towards adventurers.
Was the paladin acting according to his oath? Sure, he was doing what his god told him to do. Was the paladin
objectively good? I actually find that debatable, and I would have had objections if the DM had chosen to validate his supposed goodness by presenting him with some magical item that is supposed to measure inherent goodness.
It's a matter of taste, but note that the alignment restrictions might be LG for the Grail, but might actually be CG/CN for Mjolnir, because of where Asgard is on the Great Wheel. You might also go the way of the Weapons of Legacy, where specific acts done please or displease the weapon/object, allowing you to wield it or not, and/or develop powers. The possibilities are endless, and choosing the right one for your table is really a matter of taste.
Right, and my taste is more about the specific acts and goals of the PCs aligning with such objects. But you do make a very good point about the Grail vs Mjolnir alignments. I suppose the objects themselves can be seen to have an alignment that makes them likely to choose someone who seems to be a match.
I really do appreciate your explanation about how it works in older editions because it is very interesting. The question was about whether we use alignment in our own games, though, so I answered based on my own experiences with it.