To ensure fairness and prevent concentration, the redistribution of dormant coins will be algorithmically divided among miners based on their proportional mining power, similar to the current mining reward distribution.
1. Current mining reward distribution actually is "winner takes all".
2. Hashrate of each miner/pool only can be estimated[1] based on block they've mined.
3. How long past blocks should be checked in order to determine the distribution?
How to address coins are "lost"?
Whenever you access your wallet, a 10 year timer will begin/reset. If the wallet is not accessed again in 10 years the coins will go back to the mine. Keep in mind, i never mentioned activity (sending or receiving), simply accessing, or logging on.
Bitcoin protocol doesn't force wallet software to make log about when the address/wallet is accessed. So your idea is essentially impossible.
[1]
https://bitcoin.stackexchange.com/a/115090