Brush tool/command: Architect to Apprentice or Builder. This will aid players in making their Builder or Architect builds, taking a bit less time. Possibly adding restrictions until a higher rank.
Smooth tool/command: Architect to Builder. Same reasons and idea.
Copy/Cut/Paste tools/command: Builder to Apprentice. To make things a bit more convenient for those working towards Builder and Architect.
Plot download: Apprentice to Worker. Who doesn't like to save a schematic of their wonderful creations?
These are the only ideas I currently have for a few changes for creative rankups. Some of these are ideas that one or two other players have agreed with. Hope ya' take these into consideration.

Current list of perks for creative: http://clownercraft.net/ranks/#RankTabs-2-content