I am having fun thinking about how Lockpicking would feel if overhauled to mesh with the current profession system, instead of being a passive skill per character level.
For each content expansion, use thieves-only drops from pickpocketing to craft lockpicks and use them to unlock boxes, with profession perks to increase gold from lockboxes, increased chance to find higher quality lockboxes, or improve lockpick quality (craft an unbreakable soulbound lockpick?).
There seems to be some potential to recapture the charm of the old lockpick system, alongside updated and interesting rogue-only gameplay.