For just 1 mana, it makes every opponent discard and lose life right away, then later cashes in for a scry to smooth your draws
Furthermore, Shire Sheriff, Anguished Unmaking, and Swords to Plowshares are all exile effects which, of course, Graveyard decks hate
The ability to both draw a card when your stuff is targeted (and before resolution, so you can draw a card to respond to it) and to keep your foes from drawing more than one is very powerful for a 4/4 3-drop that gives you ramp, removal, and countering
With this in mind, its no wonder that sales have been fairly consistent since the Counter Intelligence precon was first revealed
Oko's second ability overwrites all colors and creature types the affected creature has
Tyvar the Bellicose Tyvar the Bellicose is an interesting card for its second ability more so than the first