My main problem is, the serious issues people have had with using alignment demonstrate it really hasn't been that stable.
That seems like quite the circular argument you have there. People like me complain that it's bad so therefore it's bad. I'd say it's an appeal to the masses fallacy, but I don't think the masses agree.
A lot of D&D is implemented differently at different tables. I don't see that as an issue and I don't think removing alignment would solve anything. We'd just find something else. But you also seem to primarily be complaining about versions of the game that were last current decades ago. I guess I don't really see the point of calling out BoVD, it was published nearly 20 years ago and was never a core book.Some people see it as a tool. Some people see it as merely labels, like team jerseys. Some people see it as a straitjacket, or at least behave like they do. Some see it as a wibbly-wobbly, aligny-wimey ball of stuff. Some think it's more than mere cosmic labels, but still purely descriptive, a matter of collective actions. Some think it's literal essences physically present within things, places, people.
And the problem is? Every single one of these positions can find a point in a book for at least one edition of D&D that supports their stance. Even the things that get explicitly rejected (like straitjacket stuff) are easily read into actual book text. (The BoVD and BoED are particular stinkers in this regard.)
All this is part of why I have the cosmology I have for my game. If there are going to be pure evil or pure good beings, by God I'm going to explain why they're still capable of making choices, but reliably won't make the kind of choices that would take them away from evil. In so doing, I further try to avoid Unfortunate Implications; some such implications are probably unavoidable in the grand scheme, but I can do my best. That way I can have my cake and eat it too; I can have a world where choices matter, where the soul is free, and yet also one where there are some beings that have chosen evil so hard, there's no way back for them, unless they truly cease to be the kind of being they currently are.
I agree that the implementation specifics of alignment have changed and for the most part for the better. I've pretty much always used it like 5E explicitly states now - just a general guideline, one aspect of many that can be used for role playing. We can't change the past and some DMs are always going to emphasize some aspect of the game that some players do not like. I don't see why people care about the current version.
