This has probably been suggested before, but I feel like possession should have errata:
1. Make it an attack.
2. Make it not stack (add wording similar to outpost).
Does it NEED errata? No, but I just think the world would be a better place if Possession were *slightly* weakened. Hey, they changed Masquerade, why not change Possession?
I'll suggest agreeing to ban possession in any of my individual matches in the tournament, that's for sure. Also rebuild.