Bundles are fun ways to play the game in a certain way, but levels go by quickly, which is why I think it would be a good idea for wizards to be able to pay gold or crowns to "upgrade" their bundle items. Something like this
Example: I redeemed a level 50 clothing set from a bundle, but I get to level 60 and find better gear, but I wish I had a higher tier clothing set. So I pay around 100 to 500 crowns, and my clothing set goes from the level 50 set to the level 60 set. This idea can also encourage people to buy bundles because they can upgrade their set even after they out level it.