This is the third post in what has apparently become a series on how to make skills interesting and useful. This discussion is something I wrote up a long time ago, back in the days of 2e. I thought the three-tiered approach to skill progression introduced there, and now continued by Zweihänder, was interesting because it reflected the medieval guild levels of apprentice, journeyman and master. I felt that some more use could be made of those levels, which I called Mastery, other than just +10% success.
I also felt that in an unjust society like the Empire, skill at Law would not determine the outcome so much as who was doing the judging. I therefore concentrated on the usefulness of the skill in getting a favourable jurisdiction or set of laws. The actual outcome of the trial would be determined by charm, connections, bribes and the like.
I’ve updated the discussion somewhat for 4e, but the basic assumption of three Mastery levels remains. In the case of Lore (Law), this could in the new system be reflected in levels in the Savant (Law) Talent.