The non-Secret Lair version will always be different from what the Secret Lair offered, but might keep the same name, representing the same character/object/place aka it wont always be a Universe Within version. Theres not going to be a single way to do this
Fittingly, this Planechase card gives creatures the shadow ability, a familiar effect that has great thematic overlap with certain Doctor Who monsters
Being an Artifact, Greaves can slot into literally any Commander deck, and is not as easily available as the cheaper Swiftfoot Boots
Lastly, Garruk's easy-to-access -4 ultimate ability can help push damage through to your opponents, providing each of your creatures with +3/+3 and trample until the end of the turn
You'll see :)
There are going to be eight of these in total, and each one lets players bend the commander deckbuilding rules in unique ways - such as adding instants and sorcery cards of an additional color