I know Cloak can be semi-countered by Hounding, Rain, and any physical AOE skills but the cloaker can easily move away from these.
In guild battle, a common strategy is Spiritual Link + Cloak so everyone will be hidden and rush the enemy tower. PVP will be more fun if all skills have a specific hard counter and in the case of Cloak and Burrow, there is no hard counter for it. So I suggest to put an attribute to any of the Oracle skills (maybe Forecast) that allows anyone who have the buff to see hidden enemies.
What do you guys recon?