Remove Stacking of Duskblade+Stormrazor?

Ian't it funny to die to a rengar Q late game? No? Ah riot Lied

It doesn't stack? Duskblade damage isn't increased by Stormrazor. The problem is the rediculous amount of armor pen in the game. at level 18 most champs have at least 50-100 armor base and just lethality can cut through at least 50 not counting Black Cleaver or Lord Dominik's regards. Duskblade and Stormrazor isn't the problem, assassins more or less doing true damage is.