An algorithm may be capable of serving as a multiplier to the already existing dynamic PoW solution. It can be capable of dynamically, and exponentially, increase the PoW necessary for future transactions of a wallet, and take into consideration a multitude of factors. These factors can include amount of coins being exchanged, total wallet balance and time between transactions. Each of these factors can also have a dynamic weight, increasing or decreasing with overall network traffic. As the Nano coins remain still in a wallet for longer, the algorithm slowly fades it's increments of PoW.
Maximize the costs of perfoming a spam attack while the network is under heavy load
By factoring in amount of coins per transaction, total balance and the time between transactions, a spammer will have to acquire a larger amount of coins and spread them in more wallets, in order to minimize his average PoW multiplier.
As the network grows in value, acquiring extra coins becomes more expensive.
A legitimate wallet which transacts more often will suffer a heavier penalty during heavy load times. Having a larger balance will mitigate this.
Can potentially harm network efficiency, as nodes might have to verifiy if wallets fully performed their PoW.