Non-binary saving throw results or making Save or Suck effects not suck

[Amanuensis]

This is mostly a thought experiment.

The saving throw system in its current state has some flaws. At higher levels, the gap between good saves (in combination with high ability modifiers) and bad saves (in combination with mediocre ability modifiers) grows huge. Attacks against a PC's strong save are unlikely to succeed at all, and attacks against a PC's weak save are very likely to succeed. That turns into a problem as save or die/save or suck effects with the potential to take a PC out of the fight become more common. Spending your turn paralyzed, confused, dominated, petrified, insane, polymorphed, or dead doesn't make for a great game experience, even if it's only a temporary condition. To a certain degree, it is not much different from a GM's perspective. However, I think these effects have their place in the game, both as GM and player options.

My approach would be to make saving throws less binary. In place of succeed/fail, there would be a wider spread of possible results:

saving throw result / effect
x < DC -5 ............... devastating effect (full damage + rider effect; potentially lethal effects)
DC -5 ≤ x < DC ..... major effect (full damage, major condition)
DC ≤ x < DC +5 .... minor effect (half damage, minor condition)
x > DC +5 ............... no effect

That way, SoS effects are still threatening, but they are less likely to take a character (or monster) out immediately. Failing badly against a fireball could cause the creature to catch fire; barely failing against insanity would only cause a temporary confusion; succeeding against flesh to stone might still incur Dex damage; an excellent save against poison would not require any further consecutive saves.
Additionally, for effects with repeated saves (such as hold person), each successful save could lessen the effect's severity by one step (paralyzed >> entangled + immobile >> entangled). Likewise, repeated applications of the same effect could increase its severity.

Of course, it would require an insane amount of work to create new rules for each spell or effect that requires a saving throw, even if many of them could be standardized. It would also make the game a bit more complicated. Maybe a suggestion for a future edition with a revised set of rules?

[Guru-Meditation]

The basic idea sounds promising, but it would require a rework of ALL save-or-else effects.

Would be more a thing for Pathfinder 2.0

[Create Mr. Pitt]

SoS effects don't suck. They are usually awesome. And if you makes sure your DCs are sufficiently high enough that you can land them at a percentage that definitely makes them worth casting.

There are already spells that have effects upon failure. For instance, icy prison causes entanglement and damage even on a save. Stinking Cloud provides cover regardless of save. It's a power of higher level spells. I don't think the system needs to be changed and this would only make arcane casters all the more powerful. I don't see the need to nerf casters, but I also don't see the need to make them better or to have to go through and figuring out how each spell would activate on each tier of save.

As someone who enjoys playing arcane casters while keeping the game moving I don't think the classes need another set of layers to keep in mind. I appreciate the idea, spells with lesser effects are amongst my favorite to cast, but I think this is a step too far.

[Amanuensis]

I was mostly thinking from the GM's perspective. Using these effects against players can be a tricky thing. Finger of death or baleful polymorph are great spells to tell your players that you mean business, but it also means that there is a chance that one of your players will have to wait the combat out. I want to create an impression of danger without making the game too deadly. And I don't aim to increase the power of casters (I guess I should have been more careful with my examples).

[Arnakalar]

Strongly reminds me of where Mutants and Masterminds took Afflictions when they moved off d20 open game license.