I think it would be a cool thing to "stitch" our pet's talents with with different appearances. I say this because there are a lot of crown pets that can't be used in the kiosk and many of them look cool but are potentially worthless due to not being able to hatch them. So it would be useful to have pet "stitching" in order to utilize the many pets we have and have more creative freedom in game.
That would be a great idea! For example, tons of people use the level 108 pets as well as the primeval hoard pack pets because of the cards they give and the set bonus they give. I think an elixir could be used that polymorphs your pet into another pet, transferring all stats, set bonuses, cards onto a different pets appearance. It would encourage players to use all the cool pets that are released and never used.