The fear range on Shaco's boxes is actually quite similar to the Oracles radius of detection. They can still manage to fear people if they're not paying attention. Not to mention they still act as relevant deterrents to all-ins, since even with Oracles, the boxes will fear and attack as soon as someone snowballs into them.
As far as his Q goes, yeah it's kinda a pain. But if you're at that point in the game where everyone has the money lying around to buy Oracles, Shaco likely isn't doing much anyway besides clean-up duty.
With Teemo, Oracles may counter his proactive shroom placements (i.e. the shrooms he simply drops and waits for people to step on), but it does nothing to counteract his reactive shroom placements (i.e. the shrooms he throws into clusterfucks to do massive AOE damage). Just sit on the max number of shrooms until a fight breaks out and start throwing them at people. They'll be too preoccupied with the battle to clear them.