My unopposed system is (Skill) X:Y, where skill is something like Magic, Adventuring, or Trickery; X is the number of dice that must show >= Y to succeed. I like the system. It allows for skillful, low variance challenges (8:2) or high chance ones (4:5) or chancy tests that experts will easily get (3:4). Skills go 1-10 and each point counts for a dice to throw. Up to 2 dice can be added or subtracted for circumstance. There are no vital statistics, only skills. I also wants to keep HP low, maybe as low as 20 max for a top tier char.