The clear intention of this card is that after it is cast, it goes to exile instead of the graveyard
Having a bunch of fetchlands and a Courser actually gives you a pretty intense amount of searching to find key cards from your deck
Sometimes because of their collection value, sometimes because newer cards might be in better condition, and sometimes for the very simple fact that theyre cooler (ie, the art)
While the Rat drop does benefit from being one of the biggest drops we've seen so far (thanks to four copies of Rat Colony, which are currently worth almost $8 each, making just the Rat Colonies worth the $40 cost of the drop), the value of the cards in the drop is high enough that even if you cut the drop in half, it would still be on par with most of the other Secret Lairs , from a value perspective
Sauron can also summon armies of orcs, where there were none before
Ive previously been happy getting one creature from the top seven when casting Turntimber Symbiosis