F2pool has stopped mining STX in recent days FYI. Maybe b/c they saw this thread. Maybe b/c they were tired of being orphaned every block by The Entity. Maybe some other reason. But fwiw they are not mining right now.
In terms of these proposals, I am strongly not in favor of a minimum total commitment, for a couple of reasons. First, good-faith miners get hurt, as pointed out by @muthu.btc early in the thread. Specifically, they get hurt when they make it into a Bitcoin block that other miners didn’t make it into, whether due to flash blocks, Bitcoin network congestion (i.e. high fees), or yes Bitcoin MEV. Obviously the Bitcoin MEV case is pure value extraction, but I’d argue that the other two cases are a real service to the network. An STX miner is mining a block that otherwise wouldn’t have been mined and doing it in good faith, and the protocol should not simply take their money b/c other miners failed to get into the block.
However, that’s not even the biggest issue. The biggest issue is that the proposal exposes Stacks to catastrophic scenarios where the network simply comes to a halt. @jonkho alluded to one such scenario above, which is when the BTC/STX exchange rate rapidly shifts such that it becomes unprofitable for miners to mine even at the 90th percentile total commitment. Most miners are not going to willingly lose money, so if the mining pool is self-interested and is not asleep at the wheel, then mining will simply stop. At best someone (likely the foundation) will need to willingly mine at a loss in order to keep the network going.
A similar scenario could play out if a large STX miner leaves the pool or goes offline for any reason. That loss of that capital would surely drop the total commitment of the mining pool below the 90th percentile. Maybe the remaining miners would immediately make up the difference, but that is far from a guarantee. Those miners would need to be monitoring and actively responding to the commitments of other miners, and they would need to have significant capital readily on hand. If the former is not true, then the miner will simply get screwed as they continue to pay BTC (and mine Stacks blocks) without any opportunity to win STX rewards. If the former is true but the latter is not true, then the miner will simply stop mining for the time being, thus driving the total capital of the mining pool even further from the 90th percentile threshold.
In regards to the sliding window proposal, I like that one much better. It’s fair to good-faith miners, doesn’t expose the network to catastrophic scenarios (at least not that I can think of), and places less of a burden on miners when it comes to monitoring the actions of other miners.
Fwiw I’m also in the camp that doesn’t think the Bitcoin MEV issue is that serious, especially with F2pool having now gone offline and with a plan to Lift mining off of Bitcoin possibly on the medium-term roadmap. But if the decision is to definitely act on this and we’re choosing between these two proposals, I would strongly favor the sliding window approach.