So I'm going to pull a 180 and I'm not going to create special "saving throws" based on level. What I will do is try to figure out some notable combinations within the skill system to base reactive checks for special creature or situational effects like drain and petrification. I think that physical will likely still be the most common skill used for these things but I think that that is OK - it does pay to exercise when you are in the adventuring business.
Some initial thoughts:
- Fortitude and reflex type saves will stay the same - physical + STR or DEX respectively;
- Resisting undead draining effects or other attacks on the "spirit" perhaps Survival + CHA;
- Knowledge is a good stand in for study, focus and mental discipline - thus resisting magic in general would use Knowledge + MIND;
- Resisting illusions, glamors and other charming or persuading effects might rely on your 'more creative side' so could be Subterfuge + MIND;
- The Communication skill would impart composure and an eye for detail which would be a good basis for reactive 'notice' and surprise checks (Communication + MIND) - not exactly a "save" but useful enough to be desirable.