All thieving skills are resolved using the following progression:
Levels 1-2: 2 in 6
Levels 3-5: 3 in 6
Levels 6-9: 4 in 6
Levels 10-14: 5 in 6
Levels 15+: 1% chance of failure
This is pretty much how it goes for Hear Noise, but it seems so simple and intuitive that I can't see any reason not to use it for all the other skills. The only significant downside is that Climb Walls takes a significant hit, but the chances of success for all the other skills are markedly improved (with some exceptions at 5th and 9th levels). I think this makes low-level thieves more effective, and thus more enjoyable to play.
One variant that I'm also considering is using an equivalent d12 regime, with high DEX giving a +1 bonus.