Honestly, I think many miners already switched back to something else. On flypool you can see the hashrate already dropped, so I wouldn't worry too much. Also ZEC is still going down in price and everyone bashes ZEC as being a shitty coin so my guess is, that a speed increase will actually profit longer than 1 or 2 days. Also, if you optimised your rigs properly, they should still use less power than ETH.