So that was it... 6 hours after the fork and profitabilty is back to what it was before.
Looks like Nicehash wasn't destroying the algo after all.
GPU miners have become a lot nimbler nowadays. Doesn't take long to switch miners to a new algo and close the arbitrage window.
It's not only that, NiceHash creates an easy way to direct attacks on a network, not just probability. Dat 5% dev reward tho :\