Blade's master skill is the ability to dual wield any one handed sword. The same applies for blunt
Then there could be a dual wield blade skill & blunt skill.
Dual Wield Blade
Novice-Dual wield daggers cannot do power attacks
Apprentice-Dual wield daggers can do power attacks
Journeyman-Dual Wield short swords can do power attacks
Expert-Dual Wield longsowrds can do power attacks
Master-Can paralyze enemy with forward power attack, can disarm with sideways power attack.
This also applies for blunt & I have not used blunt so I don't know about it.
The fall back is no blocking & more fatigue. The birght side is you will do 2x the damage faster. There can also be a power attack were you hit them with both swords at once.
The Final way is just dual wield in itself as a skill. LIke it would not be blade or blunt, but all applicable weapons.
If this is in Skyrim I will use it no matter what.