I think the blades deal good damage, only there should be a way to tone the damage down for the players.
(thinking about evasion for lesser damage or let ac have effect it and damage reduction should always work against it)
In D&D there should be no attack where you can't lower or evade the damage.
Even a firewall where you stand in gets reduced with fire resistance and fire protection.
And there are already to many reasons to have as much hitpoints as possible, else some classes are even less liked (melee rangers, rogues).