You have to consider the hero or villain and what they most likely would require in a mech as a compliment and embodiment of there own abilities(not necessarily powers). For instance (i will try and use examples for characters that don't already have submitted mechs as not to favor anyone), a character who is mostly ranged would most likely used ranged attacks/weapons such as Gambit or Havok, etc. Also, a character who is mostly or all melee would not have ranged weapons and instead would use their mech to enhance there close combat fighting style such as Catwoman, Colosus, or Mr. Fantastic, etc. This being said, it could go the other way, its all up to the imagination of the creator.
In the end we can all be total nerds and try and split hairs about whats a weapon and what is not, but this contest's most important rule is to just have fun and see what people can come up with. Lets just all be civil and let imagination drive creativity.
Fear is the path to the dark side. Fear leads to anger. Anger leads to hate. Hate leads to suffering. -Yoda