Several years ago, I proposed a DPS Cap mechanic, in order to reduce the amount of optimization in DPS gameplay.
Surprisingly, Eve Online is going to implement a similar idea in their new Citadels expansion. The cap is on the target citadel, as there is a maximum amount of DPS that can be applied by attackers during a battle. Extra damage past the cap is just absorbed and disappears.
The intention here is to avoid requiring larger and larger fleets, and to stop an arms race between fleet size and citadel hitpoints. Instead, any fleet above a specific size will be "good enough" to take a citadel. Additionally, the DPS cap guarantees a minimum time that the citadel will be alive in a fight.
There are some other interesting wrinkles. For example, the citadel cannot be repaired or "healed" by friendly ships. I think it will start repairing itself after some time passes, though.
The DPS Cap mechanic is different than the one I proposed. It's on the defender, as a defensive mechanism. So from the attacker's perspective, it's a limit on the fleet, not on individual ships.
Still, I think this is an untouched area, and we will see more experimentation. I think this is especially true for world PvP games where there can be a large disparity between the two sides.