If you want to go with the Sandals of Hermes granting a sort of super-speed effect, Enhanced Agility, Quickness, and Flight are probably the way to go.
I recently built a character who used a xiphos (greek sword) of Zeus that had a Blast (lightning) effect as the main power, then with Strength-based Damage to represent the sword's actual blade. Affects Insubstantial reflects its magical nature, and you could certainly justify quite a few ranks of Improved Critical as well.
As for a Spear, maybe a throwing spear that, when thrown, actually splits into dozens. Multiattack Blast, or maybe Blast with Shapeable Area.