New DPS King: Gengar | New Best Attacker: Machamp
According to my calculations, Gengar with Hex + Shadow Ball is the new DPS king.
This move set has a STAB cycle DPS (neutral damage assumed; without accounting for the ATK stat) of 23.81. In comparison, Dragonite's DB+DC is 19.46, Tyranitar's Bite + Stone Edge is 17.57, Alakazam's Psycho Cut + Futuresight is 17.11, Exeggutor's Zen Headbutt + Solar Beam is 18.34. Gengar's second highest DPS move set, Hex + Sludge Bomb, yields 22.49, still far ahead of others.
Machamp, on the other hand, loses just by a little. His Counter + Dynamic Punch yields 22.90. And his Counter + Close Combat yields 20.76. Besides, he's more reliable than Gengar, due to his higher STM.
What's more, Machamp has a far wider usage than Gengar, dealing with Normal Type Tank (Blissey, Snorlax), Dark+Rock Tyranitar, and the rising Iron Type.
It concludes that Machamp should be the new best attacker in the meta.