I got to thinking about the newer monsters from newer worlds, and thought "Why shouldn't the places that existed before them be in on their new looks?" I'm talking about a cosmetic makeover making a few golems around Marleybone look like the ones in Celetia's science Center. Sand Swirler variations can replace a few colossi. Or some cat burglars can be made to look more like those cat swordsmen that originated in Pirate101. In fact, certain Pirate versions of sharks and crabs are battled in the Zafaria Telegraph Box, so those skeletons have all the animations needed to be retrofitted into Crab Alley or Celestia.
I'm not saying replace all the monsters of these types, just a few to give the monster population a bit more diversity.