Mega Sharpedo got a HUGE boost in OU viability thanks to the addition of Psychic Fang (base 85, breaks screens).
Max Attack Naughty (or Adamant if you go Waterfall over Hydro Pump) Psychic Fang OHKOS Keldeo (which is 3HKO'd by Crunch), 2HKOs Banded Azumarill (who gets 2HKO'd by Poison Jab but Ice Fang is far more common), 2HKOs Defensive Mega Venusaur (Crunch does under 50%) and Defensive Chesnaught (which wasn't 2HKO'd by Ice Fang or Poison Jab), OHKOs AV Conkeldurr, obliterates Mega Lopunny (which normally gets 3HKO'd by Crunch most of the time, and only 2HKO'd by Waterfall), and 2HKO's Clef with some prior damage (although Poison Fang/Jab always 2HKO's here).
Oh, and it'll let Mega Sharpedo muscle past the new fat Water/Poison too with ease, something that a lot of physical attackers will have trouble with.
That is a TON of common Mega Sharpedo checks and counters that are either cleanly OHKO'd or 2HKO'd on the switch. Sure, you're still frail and not too fast without +1 from Speed Boost and kinda need Protect, but this is still a huge buff to viability in terms of making Mega Sharpedo a late-game cleaner.