I mean, it's a weird line to draw from "% chance to succeed at climbing, moving silently, hiding in shadows, hearing stuff, detecting secret doors, etc." to "the best at leveraging the generic competency system." If anything, this should be conceived as the rogue having a significant bonus to a quite specific set of skills, or some unique mechanics to reroll or auto-succeed such checks. I'm not sure "master of a unique domain of mundane expertise" actually fits comfortably on the rogue chassis; that feels like it should be some kind of Sage or Adventurer or something else class that doesn't have the Thief baggage and/or sneaky Dexterity combatant focus.