Its most strong when used on an opponents' draw step, so you can take the chance of exiling their draw on top of the copies from their deck
Commons (C) are simple, abundant workhorses, forming the backbone of decks, especially in Draft and Sealed formats
Activating a Walking Ballista is nice because it represents an extra point of power and toughness and well as an additional point of damage that can be thrown around at the Constructs owners discretion, but four mana isnt a small amount
All in all, the one-of-one One Ring is up there with one of the games best marketing campaigns, arguably even the best, and we can expect much more of this kind of thing going forward.
This means that Shock lands, Battle lands, the dual snow lands, and even the original dual lands are searchable with these two spells