Is There Logic Behind Old-School Saving Throw Tables?

In my last post I gave some reasons why I like the original D&D saving throws as a general concept. Wanting to make up my own setting-specific saves took me down the rabbit hole of looking over the old books and trying to figure out the logic behind the actual numbers that are given for different saves. I looked over my copies of the Rules Cyclopedia, the AD&D Dungeon Master's Guide, and Lamentations of the Flame Princess.

The short answer is that I think it's all basically arbitrary, though I'd be interested to hear if anyone wants to correct me.

The long answer is this:

How do the classes compare?

- In RC and LotFP, which use race-as-class, the demihuman classes all have superior saves to any of the human classes. I guess this makes sense in RC where the demihumans are sort of like rare Pokemon due to their stat requirements. It doesn't make that much sense in LotFP, but I imagine that Raggi just copied it over for the sake of tradition.
- Halflings have the best saves in the game in both RC and LotFP. This makes sense in the same way as Dungeon Crawl Classics giving special Luck bonuses to Halflings - the logic being, if Halflings aren't supernaturally lucky, then why aren't they all dead already?
- AD&D separates race from class, so it only has four saving throw tables for the four 'core' classes.

- In all three books, there is a common theme of Thieves/Specialists having the worst saves, Clerics being middling, and Fighters starting out poorly but gaining saves at a faster rate until they eventually overtake the other core classes.

How do the individual saves compare?
Mostly, the numbers for each save seem to have been picked more or less at random. There are a few points of intentionality that stick out:
- Breath Weapon is consistently the hardest saving throw to make, across all classes. I suppose this was to make dragons especially threatening.
- Magic-Users often have the best saving throw against spells, implying they have a chance to counter the magic with their own. Clerics have the best saves against Poison/Death Magic, which also seems thematic. I can't see any other places where one class is notably good at a particular save. And even in the case of the Cleric, it's probably going to make a difference of 20% at most, on a roll that is not going to come up all that often over the character's lifespan.

How do the different books compare to each other?
- LotFP has roughly the same numbers as the RC, but they're usually better by one or two points. Maybe that was Raggi's idea of giving his players a break?
- AD&D's numbers are totally different to the RC's. For example, a first level AD&D Fighter has a Poison save of 16, whereas the same save in RC is 12. What's more, AD&D Fighters improve their saves every two levels instead of every three.

It's at this point that I start to doubt that there was any real logic or maths happening behind the scenes when Gygax and other designers were choosing these numbers. I know that some people like to read into AD&D and find hidden nuggets of wisdom, but it seems just as likely to me that Gygax just made up a bunch of new numbers so he could say his game was different from Basic D&D.

Frankly, trying to wrap my head around all these tables feels like more cognitive effort than it's worth for the amount of impact it will have on gameplay. The complexity of the tables feels like a sham - an effort to keep the game's design mysterious by obscuring how banal and arbitrary it really is.

If I were going to write a new, setting-specific table of saving throws, I'd be inclined to just write one table that applies to all characters. However, I would take two lessons from my analysis of the old-school tables:
- You can emphasise a particular danger by making it a harder save (for example, dragon breath.)
- You can emphasise the 'luck' of a particular class by giving them a bonus to saving throws or a separate saving throw table. The latter is a bit more clunky, but I think it's worth it because it will make the player feel like their character is "breaking the game" in a cool way.