The weapon quality increases by one tier, but without enhancing the attributes or the effects of attached skills, it may seem underwhelming.
Actually, under normal circumstances, this skill enhancement was quite excellent. It could elevate the quality of a weapon by one tier. Melee weapons had increased output, while ranged weapons benefited from better mana conduction efficiency, resulting in a boost in skill power.
Moreover, since it's an unconditional quality boost, Sterl's future legendary, epic, or mythical weapons will benefit greatly from this skill, making it extremely overpowered.
Higher-tier weapons experience a qualitative change with each tier increase.
Sterl was exceedingly excited, though slightly frustrated by the effort required to achieve 'Mastered' proficiency in [Mastery: All Soldiers].