I don't think it's top. Damage over Time specs typically top Burst damage, so I call shenanagins unless he's better geared or just a superior player.
FWIW, to me the problem with pre 1.4 deception assassins was always the damage vs survivability element.
They did okay damage but they died way to easily, so
-Most of the end game armorings had more endurance that willpower (which lowers damage)
-Some players felt the need to forgoe damage skills for utility skills than increase survivability
So after 1.4, Assassins pretty much have a rolling 6% damage reduction (2% per crit, stacks 3 times) and they have a 25% damage reduction when dark embrace is active (not to mention a lower cooldown on Force Cloak). Also a big change was Crackling Blast was a 5 point skill (added 10% crit damage to discharge/shock) and is now a two point skill, so there's room to take a skill like Insulation (armor rating increases by 30%), without forgoing a damage skill.
So overall the damage is the same, but survivability is way up