If Dual Blades debuffs its own damage type, I foresee it being the most popular set EVER.
Imagine, a scrapper, tanker, brute or stalker (lol) that can debuff Lethal resistance when a majority of enemies in middle and upper end CoH have moderate to extreme Lethal resistance? Every lethal-damage set player in the game would want their very own Dual Blades buddy.
Psionic weaponry wouldn't have to be a ripoff of Psylocke. Just don't make it a purple katana. Learnt that lesson after ripping off Wolvy's claws. Maybe a nice energy spear you jab into your enemies, invading their mind and inflicting Fear as you punch through.