An idea I've always fancied for representing "masterwork" and other such high-quality weapons is something more dynamic than a simple +1 to hit. Because while in theory, a masterwork weapon may be easier to wield and use, or aim, I was never very keen on the constant and infinite scalability of modifiers in Third Edition and newer. It just seems too lazy and repetitious.
So instead, my idea is that in place of adding a 'to hit' modifier, that the masterwork weapon, rather shift how it deals damage when it hits. Take for example, a weapon that normally deals 1d8 damage by itself, will deal 2d4 damage as a masterclass weapon. This allows weapons to deal greater averages in damage, which if using hit points similarly to how I do, this still works out as making it easier for the attacker to hit. If only because the attacked need dodge harder to avoid a lethal blow, wearing themselves out faster.
And if nothing else, it just makes for more dynamic weapons; though the potential for making attacks tedious becomes a possibility for weapons that already use two dice in attacking. As an advantage for magic-scarce games, the fighter can have a slightly better sword without it having to be a +1 or better magic sword.