I dont think there are many cards that summarize the reaction of the people of Zendikar in the face of the Eldrazi as well as Soul's Attendant
The Doctors in this set have a wide and weird variety of abilities, ranging from boosts to Historic cards to granting additional upkeep steps
I just couldnt afford to drop $70 every couple of months (or $140+ considering that the next expansion set, IIRC, had twice as many cards)
It's an artifact that can store aether (mana), temporarily locks away a foe, and must be destroyed before time runs out
The tapped clause disrupts certain infinite combos and helps aggressive strategies since it messes with your opponents ability to block
Sothera, the Supervoid Ive seen people bemoaning Sothera, the Supervoid as another Grave Pact/Dictate of Erebos-style effect, but I think theres some nuance here