The two with the repeatable on going ability are the more powerful and useful ones in my eyes
Next this is the color from my first two mono-colored cards combined in one legendary leader
(I couldnt stop thinking of the distinctly un-Disney image of Tigger being melted into a pot of steaming ink, Roger Rabbit-style.) Another key difference - and one that feels decidedly Disney - is that players arent competing to grind their opponent into the floor by chopping away at life points with attacks
Archmage of Runes has a nice pedigree to see play, and being a 3/6 giant wizard helps, because you have good stats and good creature types
I also really love that it makes it much harder to abuse cascade, discover, and other engines that let opponents cast big spells from exile
If the opponent survives that attack, the second ability will greatly speed up the game with so much extra damage to the opponent's face