When compared to its numerical predecessor, several differences stand out
Sisay offers flexibility in deck building with legend permanent tutoring and power scaling
For Sieges, the battle must always be protected by an opponent of the controller if the protect leaves the game, the controller must instead choose a different opponent to protect it
Id sacrifice Composite Golem, bring it back with Nim Deathmantle and dump all that mana into a storm of spells (to go wide), or a single card like Walking Ballista/Golem Artisan to close out the game
Depart the Realm This is definitely a playable card in my opinion, and there's a weird playable loop for it, and you can just get it out of your hand and then use it when you need it
You spent four Black mana and drew 7 cards for 7 life