Hey Sarissofoi,
actually the nimble perk working for two-handed weapons was kind of a bug/oversight by us. As it says in the tooltip: 100% melee defense “if the offhand is free” which is not the case when wielding a two handed weapon :)
The intention behind this was making it possible to have viable one handed builds (like the duelist) or add some defense to your tanks in case their shield gets destroyed in the heat of battle.