I've seen a couple people promoting the idea of 2d6 skill rolls, and at least one person -- don't recall who -- suggesting using the reaction table to interpret results. I prefer avoiding a skill system, but there's a certain niftiness to that idea. I did do something like that with Con rolls for adversity (aka "system shock". Roll 2d6 under Con to survive, but if the roll fails, look up the roll on the reaction roll table (or custom death and dismemberment table derived from it.)
What I'm thinking is that there's an easier way to adapt this to improvised ability checks. Here are the rules:
1. Roll 2d6 under relevant ability.
2. Halve the ability score if it's a particularly dire situation.
3. If the roll is less than/equal to the ability score (or half the ability score,) it's a success, with the reaction roll indicating the degree of success.
Hostile/Bad results (5 or less) mean the check succeeds, but with a minor penalty. Very Bad (2) means a major penalty. Good results (9+) mean a slight bonus, and Very Good (12) are even better. Some suggestions:
Physical Adversity rolls: Roll under Con, or half Con for severe disease. Bad means a scar, Very Bad means a limp or lingering condition, Good means a slightly quicker recovery, Very Good halves the recovery time.
Raise Dead rolls: As Physical Adversity, but you need to decide whether all Raise Dead attempts count as "dire", or just the second attempt, or each character gets one "non-dire" roll every 4 levels.
Thievery rolls: Roll under Dex for thieves, half Dex for anyone else. Bad means it takes twice as long or you only take half of the loot or the thievery will be noticed after a short delay (result = turns; you have that long to get out before the victim notices.) Good means the victim won't notice for days unless told.
Search rolls: Roll under Int or Wis, but only if player doesn't do something that would obviously find the item. Bad means it takes twice as long, Very Bad could mean an accident, like brreaking something or making a loud noise. Good takes half as long, and Very Good is nearly instantaneous success.
I'll post about an advanced option later.