For miner perspective, they will be at loss when ETH going to Proof of Stake because they still haven't ROI from ASIC miners they bought.
Some miners may already started to mine other ethash coin such as ETC, thus the mining hash rate will moving from ETH to ETC, resulting spiking hash rate on ETC.
After the hashrate increases, the difficulty of mining new coins will increase. And this will entail a decrease in mining profits if the ETC price remains at the same level. ETHW mining will remain the most optimal for miners if the price of the coin remains in approximately this niche, which ETH currently has, but it is hardly worth counting on.