When using the Shift 5 ability, which allows the six-cost card to be played one turn early if a cheaper Merlin can be commandeered for the cause, Merlin gets to make use of another feature called Overdeveloped Brain
Not to mention, if you're looking at an older core set card from before Sixth Edition , there may not even be an expansion symbol at all
The Leaders released in OP08 include: Tony Tony Chopper (Red/Green) Marco (Red/Blue) Carrot (Green) King (Purple/Black) Charlotte Pudding (Purple/Yellow) Kalgara (Yellow) PRB-01 The Best Theres just one new Leaders being released in PRB-01: Sanji (Red)
Stella Lee, Derevi, and others bring diverse playstyles and challenges, encouraging creative deckbuilding and strategic sequencing
That's huge, because it means Iron Man, Titan of Innovation almost always puts your best 1-mana artifact into play the first turn it hits the board