What do you think they're going to be like? Like Halo where you punch with your gun or like every other FPS where you use a knife? Do you even think it's going to have a melee button? Maybe instead of a melee button we'll have melee weapons? What do you think?
I think my preferred choice would be for melee weapons to be an equippable, upgradeable, category of SUB-weapon. I do think, largely for logic's sake, the game should focus on being a shooter, but at the same time for the sake of the RPG elements and personal customization I would like to get better combat knives or bayonets or whatever as I improve my character.
In the end it would be great to have a 2000 year old alien space knife, but I'm still going to use my handcannon 90% of the time.
That said, it would be fun just on the "I want to do everything" level to be able to pull into 3rd person as someone suggested and have epic knife fights or something.
I do not really want swords or hammers for example, I think it would detract a bit from the vision that they seem to be going for.