I'm not sure how or when or why Alignment has become such a...nexus for disagreement or consternation for so many in the past few decades/iterations of the game.
It really isn't a complicated, nor a "worthless," thing. It is the ethics and morals of the character. A pretty darn important piece of the character really. Whether you want an intense, detailed game of dealing in all the moral greys. Or just want a "surface" game of good guys v. bad guys and in depth examination of motivations or permutations of good/evil/law/order/chaos (/neutrality?) is completely glossed over.
That's what alignment is. That has really never been in question.
If the issue is, "It's not fair that my cleric or paladin has to XYZ....," then, the solution there is....don't play a cleric or paladin. Adherence to alignment and matching the tenets of your religion (/faith/philosophy/ideal/ however you like to fluff your "divine magic" people) is an innate and inherent part of those classes. Their definitions and descriptions...for the entirety of their existence in this game.
Not acting with sincere devotion, and appropriate actions to back it up, means lessening or losing your magic/powers. That's just part of the story of those types of characters...that's not "punishment." By definition, those classes, those characters, WANT to serve and show and spread the powers they represent/devotions they have. NOT doing so is something, from the character's perspective (not the player's whims), their alignment is something they put EFFORT into keeping/furthering...usually because that's what their deity, who they seek communion/connection with beyond all things, "says so." But that fluff is all mutable.
Are they the ONLY ones who can have that be part of their story? Certainly not. But for clerics/paladins, it is a much more ingrained and inexorable part of their type of character. If that ruffles your feathers, for some/whatever reason...play something else.
If the issue is, "It doesn't really do anything but give DM's some arbitrary 'control' over my character" [Which, for the record, I have NEVER actually seen a DM use arbitrarily or abuse] and/or the "It's just some letters on my character sheet" argument... then, seems to me, the simplest solution there is to give Alignment an actual mechanic for all the "game-as-mechanics" people.
It can/could be super simple. Even just a...pfft, I dunno, five point scale. 1-thru-5 points on some chart.
1 = The player did a terrible job adhering to your character's stated alignment/acted in direct opposition to it
and 5 = perfectly exemplified your alignment.
2 and 4 = you leaned notably more one way or the other.
3 = you didn't really lean any given direction, but didn't do anything egregiously unethical or amoral (for your alignment) either. The evil guy might have a moment of compassion or kindness. The good guy might tell a lie to get past the guard as part of the big plan for a "greater good" result, etc...
You get assigned those points at the end of each session and they accumulate.
These points are usable in your sessions (giving the player agency):
- reroll a failed save (1 point)
- or reroll a failed attack roll (2 points)
- or may add 1 to 3 points (player's choice) to an initiative or skill roll.
On the DM's side, these points are tallied up per...well, let's say 5 again... 5 sessions. There are consequences for your character's ethical and moral choices and actions (giving the DM their appropriate role and power as final adjudicator):
- If you do not accumulate a minimum of 15 Alignment points over 5 sessions, your alignment is changed/altered one shift along the Law-Chaos or Good-Evil axis. Dm's determination based on your character's actions.
- If you have only 5 points after 5 sessions, you are automatically shifted to the diametrically opposed alignment. If true Neutrality is proposed, you are shunted into a Lawful Good/Lawful Evil or Chaotic Good/Chaotic Evil alignment, depending on the DM's assessment of your actions.
- If you have 25 (or 20+?) points after 5 sessions...there's some kind of -tangible, mechanical- reward/boon (that I'm not coming up with right now because this is already too long).
Poof. Alignment "means something" and has automatic tangible consequences and [mechanical] benefits/penalties within the game.