[potatolicious]

TF2 is a glimpse into that - you can pay for weapons that are different, but not strictly better.

The Degreaser flamethrower in TF2, for example, is a non-stock item that lets you switch weapons faster, but also reduces the burn duration of enemies you set on fire.

Hell, you don't even need to be trying to monetize to screw this up. See: Modern Warfare multiplayer and its propensity for handing strictly better weapons to veteran players, resulting in even more lopsidedness in matches.