If the identity of a deck is what shapes the narrative of building and playing a deck, ownership is what allows us to invest emotionally in that narrative
Mutating Brokkos onto an infect creature can make it a huge threat, especially if that creature has other strong keywords like Plague Stinger
Reveillark is a fantastic card, but including your commander (and it's iffy to toss your commander into the graveyard) you only have 7 reanimation targets for it to hit
Another common issue you might have is finding out that you have several different versions of MTGA installed
That being said future printings might buff Wrenn and Six since its potential for being a land recurring threat are high, but for what Modern is now I dont really believe W6 deserves the second place, or to rephrase it: Definitely not in comparison to Shardless Agent
So theres our working 3-part definition for disruptor cards in Commander: surprising, affects entire board states, and likely to hurt you too