D&D 5e has been optimized to make it simple to learn and play, which is what you are reacting to. Its design reflects the fracturing of the D&D fanbase after 4e, and to a certain extent embraces a more “old-school” (read: 2e or earlier) playstyle in which the rules are much more nebulous, fluid, and handled ad hoc by the DM. This both makes it simpler to learn and play (since there aren’t rules to learn, you just have to trust the DM’s judgment), and also mollifies some of the critics of 4e (and, to an extent, 3e) in an effort to reunite the fanbase.
The downside of this is that more of the experience is riding on the DM’s expertise and judgment, and the players are often not left with a lot of surety in terms of how things will work from one DM to another. That makes it difficult to plan on things as a player, and can in some cases reduce player agency.
Pathfinder 1e was a spin-off of D&D 3.5e, and is for the most part identical in its foundations to that system.1 D&D 3.5e was likely never intended to be, but in some ways it was a departure from 2e when it comes to the subject of “rules vs. rulings,” as the more precise language gave many readers the basic assumption that things would generally go mostly by the rules and that exceptions would be, well, exceptional. Pathfinder inherited this heritage, though Paizo tried to repudiate it, and despite the fact that, like 5e, Pathfinder was in large part a reaction against D&D 4e, which was the system that most truly embraced the “rules” side of “rules vs. rulings.”
With Pathfinder 2e, Paizo has seemed to, at least somewhat, more fully embrace this “rules over rulings” ethos, in a way they largely didn’t with Pathfinder. And, in ways that are probably not coincidental but I’m not sure were planned, Pathfinder 2e is actually reminiscent of D&D 4e. The lists of class feats feel very similar to 4e’s lists of powers for each class, and the use of tags is very similar to 4e. Even the design and layout of the book feels like 4e—the little action diamonds just look like 4e’s heavy usage of the ♦ character in power descriptions, and the nature of the one-two-or-three diamonds is similar to 4e’s color coding by power availability (at-will, encounter, daily).
Paizo has also discussed PF 2e in these terms, describing their audience as being more technically-minded, more interested in the rules themselves, as being interested in digging into them and combining them in creative ways. It would seem that these appearances are not merely superficial, and possibly unlike Pathfinder 1e, not unintentional.
The long and short of it is, yes, it is fairly likely that Pathfinder 2e is at least intended to cater more to your tastes than D&D 5e is. You may also want to take a look at D&D 4e—which, as I mentioned, probably wins overall in “rules over rulings,” even more so than Pathfinder 2e.
- Pathfinder 1e’s Core Rulebook and Bestiary are based on, and in most things have the same rules as, 3.5e’s Player’s Handbook, Dungeon Master’s Guide, and Monster Manual. Pathfinder could not reference 3.5e’s supplements (as they were not open-game content), and of course Pathfinder’s own supplements after Core Rulebook were never available in 3.5e.
Best Answer
Fortune/Misfortune Effects
Many affects allow the player to re-roll saves, either for good (Fortune effects) or ill (Misfortune effects). All of these would need to be revisited on a case by case basis to see how they would interact with your change. This includes Hero Points, as @brandon mentions, but also many important feats and abilities:
Most of the above can be pretty easily converted to instead make the enemy re-reroll appropriately, but there's all sorts of small things you'd need to watch out for - for example, does Incredible Luck grant the circumstance bonus to the player's save DC? Or do you apply it as a circumstance penalty to the enemy? (I recommend the former).
The Bigger Problem: Math
Again, this can be accounted for, but it's not as simple as just switching from the DC with +/- 10. It's a little counterintuitive, so here's an illustration: Bocephus the Goblin has a +10 Reflex Save, and Abraxias the Evil Wizard casts Fireball on him with a Spell DC of 20. Results for the normal rules (die roll, save result):
This means there's: 5% Crit Fail, 40% Fail, 50% Success, 5% Critical Success
However, if you have Abraxias roll at +10 vs Bocephus's Reflex DC of 20, you get:
That means now Bocephus has a:
That's a huge swing in the favor of Abraxias. If you apply the same rules to players and monsters, it's at least seems equally penalizing to both sides, but many monsters already have a higher Spell Attack to compensate for this, so the players will still be extra penalized. If you want to make the math work, you could try adding 12 to Bocephus's Reflex Save to get his DC... but even then, as @Ruse points out, that alone doesn't solve it. Even using 12 instead of 10, Abraxias would critically fail (aka Bocephus would critically succeed) when he rolls a 2 or 1. So you'd have to make critical failures for this roll only happen when failing by more than 10. Again, not impossible, but I prefer to minimize complications at the table, and having two different DCs with different rules (one for normal things, like Demoralize, another for inverted saves like getting Fireballed) for each save seems awkward. (As a side note, getting to be the one rolling the die is an often overlooked advantage of Spell Attack spells.)
I've never met a player who doesn't want to roll dice
I've not played Pathfinder with everyone on planet Earth (yet), so I can't say for certain... but every player wants to roll dice. It's fun. I wouldn't recommend rulings that cause players to roll less dice, especially outside of their turn, when player engagement is at its most difficult. It's not really as fun to just watch the GM do everything as it is to get to roll dice in response to the GM doing things.