I actually played this out using a point system one time. There were 5 possible points, under the criteria of:
-physical strength (being physically strong)
-physical weakness (not having physical weakness)
-mental strength (being mentally strong)
-mental weakness (not having mental weakness)
-and power (having the strongest powers)
I eventually decided that since Loki grew up on Asgard, he wins both physical points. Wanda, not only gets the power point, but a bonus point in that category for being just super powerful. As for the mental rounds, however, since everyone’s powers are left in the power round, Wanda can’t wave her fingers an project an illusion in Loki’s mind. He is the better manipulator, giving him the mental strength point. As fo mental weakness, while both of them have weaknesses, Wanda is more sensitive to hers than Loki is for his. He wins the mental weakness point, and pushes the score 4-2. However, i think there’s a rock-paper-scissors relationship with Loki, Wanda, and Carol Danvers.