Honestly, good riddens to ability drain and level drain without some chance of avoidance. Average fighter, despite some great combat related abilities, has a very limited way of removing preventing any drain, and it takes days to get the full potential back. If ability drain healed faster it wouldn't be so bad, but that isn't always an option.
Best example of this was one fight against Shadows (theoretically, I don't remember the actual specifics), 5 5th level PCs were in the party, one cleric. We had 4 people get drained, 1 of them lost 6 strength, 2 lost 3 strength, the final lost 5 strength. Our cleric had one lesser restoration and healed 4 str from the 6.
Which meant our party was still down -2 on one guy, -3 on two people, and -5 on another, from a battle with 4 shadows. We are in a dungeon without much time to rest. We've had 2 days go by so far, and that one fight is still draining a good deal of our strength. Our cleric had to ditch one third of his spells to restore our strength one day, which made him much weaker too. Anything that can mess up a party for several days is a bit powerful in my mind.
Better to make ability drain come back much faster, but failing that, give an ability to protect against it to everyone without some special ability.
Wizards get some protections against this sort of damage, as well as the ability to better compensate for drained abilities (memorizing bull's strength if their strength gets drained).
Clerics can remove the effects entirely, or prevent them entirely, so they're fine.
Rogues and fighters really get messed up by these abilities, over an extended period of time. I think two saves might be over doing it a bit, but I far prefer this system overall.