There are already a lot of mixed reviews on the Magic: The Gathering Commander Bracket system, but at an absolute minimum, this system delivers a coherent watchlist for Commander cards to be moved on and off the banlist, which is a massive victory for Magics biggest format.
At worst, its counter something unless they pay two and the choosing of the spell might get around a few corner cases
This was more of a luck (or unluck) of the draw type of deal
Similar to a reanimation deck, you can use Athreoss ability to ensure an important permanent sticks around and take advantage of ETB effects multiple times
Threaten effects, or effects that temporarily steal opposing creatures, aren't super popular in Commander, though the equation certainly changes when that threat's attached to a 10/10 and also morphs the 'borrowed' creature into an annihilating monster for the turn
If they had, this card would have shot up my charts and made top five