Looking at EPT makes me think a bit more critically about ability scores. The classic D&D model of 3-18 scores with secondary modifiers means ability scores have limited purpose or value (the old school model in which extremes have a mechanical effect) or that they have a great deal of influence (3.0 edition on), but only because modifiers an the high scores that go with them are essential.
There are more subtle approaches. Systems like Fudge and Marvel Superheroes introduce some interesting mechanics around qualitative descriptive rankings. Some games (like Talislanta) use modifiers as scores. Storyteller systems use pips, etc. But conceptualizing what one dot of strength or feeble strength means can be challenging to explain.
EPT ranks abilities 1- 100, allowing them to show a range of numbers on a known scale and to serve as a simple task resolution system. Other games have done this since to differing degrees, but this still excites me. What's the chance of a STR 57 have of forcing a non-fortified door? 57%. Maybe a barred one we half that.
Hey, but there's more we can do. We can tie that score to quality of result. If you succeed, you succeed by an amount equal to the percent rolled. You have an 80% Strength and try to lift a portcullis to your waist. You roll 50 and you're halfway there. The guards get a little closer, and you have to succeed again....
I do have problems with the swinginess of flat percentile rolls to determine ability scores. I want some curve on that distribution, and firm limits on the minimum and maximum. There are also some problems I have with flat percentages since results are also too swingy in play, but I bet my Basic RolePlaying rules that this is more a problem in my head than in play.
Which all says that thanks to Mike saying he's thinking about making a generic EPT clone, I am back to thinking about what I can take from Dr. Barker's funky white box variant.