When you think that you have it all is the moment that you can lose it. Don't think ahead if you can't think for the present.
Exactly, and the Hummingbird is the nickname for the sword due to the sound emitted by the blade as it softly hums, much like a humming bird, which is a very powerful bird as well since it can beat it's wings hundreds of times per minute.
Dude, no matter how you say it, the shotgun is not a melee weapon, it is a projectile based piece of weaponry that fires slugs, which, as you say, is at melee range, but not the same thing as hand to hand combat.
Humans should have at least one melee weapon in the game, because one, it could actually be part of a unique weapon triangle:
Energy sword beats Hummingbird
Hummingbird beats Gravity Hammer
Gravity Hammer Beats Energy Sword
Two, it would balance the number of weapons between the two races. And finally, it would not be a single hit kill weapon, it would take one shot to rip through the shielding, and the second to kill them. Still it would only be one kill for grunts or drones or anything unshielded. The tech from the Covies are so vast, it would be understandable that the sword is not as superior to the energy sword, but it would at least combat it.
Finally, plasma energy would be easily parted by bullet fire, so why not a heavy handed strike with a sword that can at least break the shield.