Nah I like the idea, bayonettes might be a better slightly more reasonable idea, but the implementation of solid realistic warfare close range melee weapons of some sort seems realistic to me.

Call it what you want, be creative, make something up, I'm not saying it has to be a lightsaber or a sword or even a knife or the nova knife we have now, I'm just saying close range melee weapons would be a good idea and add to play-styles.

Hell go Jack Kevorkian on their ass and carry around a satchel of lethal nerve injectors that work like our nanite injectors, just opposite. Or allow for plasma cutters that operate like our repair tools but instead deal massive damage to vehicles, turrets, and players at point blank range by slicing through their armor. Create some sort electrical or plasma weapon that stuns and drains health, or incapacitates or if we want to go the lightsaber route cuts strait through armor.

Point is its not really a bad idea, it just should require a LOT of skill points to use for its high damage potential, and cost a reasonable amount of CPU and PG.