Bumi, Katara, Ozai, and Toph bring aggressive, thematic playstyles that are perfect for players who want streamlined game plans with big payoffs
That alone might be worth the price of admission
Kefka, Court Mage // Kefka, Ruler of Ruin I just wrote a deck around this Grixis leader you can find here - ( This five-drop 4/5 transforming body has an attack trigger to make everyone discard - you too, but no worries since you'll draw equal to the number of card types discarded
They can be unfun to play against
Changeling creatures are both snails and rats, so if you cast a changeling, you can use the rat trigger to grow itself and sacrifice it later to draw cards
This side of the card is also very powerful, allowing you to cheat out cards from your opponents hands