He provides unconditional removal that every color can access and brings back all the permanents he exiled to give you a massive head start in the new game
If you want to dive more into the discussion of card advantage vs card quality, I cover this in my discussion of the best black Commander tutors in Magic when discussing the power of Imperial Seal and Vampiric Tutor
99 vs 9.99 and 7.99 As a rule, I like to run better counters in multiplayer than cheaper ones like the Desertion at 5 mana versus the harder to cast Cryptic Command at four or the cheap but hard counter what you want Swan Song
Nyxthos, Shrine to Nyx is the extremely powerful mana engine of the first "best deck" in Pioneer
I always felt Cunning Rhetoric was a little slow, where Keen Duelist was very on point
Aragorn, the Uniter More often than not, Aragorn, the Uniter is used as an aggressive creature due to its focus on offensive strategies, with abilities that trigger whenever you cast red, white, or green spells