I now consider it an honorary piece of power along with Tolarian Academy, Mana Drain and the like), it was good in every deck and oppressively good in this archetype specifically
Defensive power and Hexproof both prevent a card from targeting spells
You want to get Echoes of Eternity on the battlefield as quickly as possible, and keep it as safe as you can
The Burden Letting your opponents draw cards is usually a net downside for you, but Sauron uses the burden of their full hands against them
It is not a case of redundancy helping the effect as is often the case for cube cards
If that permanent loses all its abilities, it will still be exiled at the beginning of the next end step, and if it would leave the battlefield, it is still exiled instead