One thing I have always wanted to differentiate between in terms of Thief/Rogue/Specialist skills and basic adventuring skills is climbing. Specifically the difference between scaling a brick wall with your finger nails and climbing up a rocky crag or heck even a tree. We have all seen (or heard of) games where the GM either stops anyone without the "Climb" skill from climbing a small tree, or where anyone can climb anything, except the thief/rogue/specialist often has to make a roll where no one else does.
Thankfully the modern lexicon has brought awareness of Parkour and Free Running. So I decided to hell with it, I would make it bluntly obvious. The Rogue power "Climbing" is being upgraded/generalist to "Parkour". While I realize Parkour is a newer invention it does serve as a good explanation of the general theme. When the character races across rooftops, scampers up brick walls and otherwise moves quickly in a way that the bumbling guards have trouble following.
The rules for this will include the current rules for climbing walls, but improved to also allow rooftop races. As always this will not be an activity all classes cannot be involved with, merely an activity that the rogue with this power is much better at.