Mega Sableye is already really good. He struggles in the current metagame because of the prevalence of strong fairy types like Koko, Lele, Fini, and Magearna, but he's still very strong, with a ton of different options.
>Stall teams: Knock Off/Protect/Recover/Wisp
>Counter offense: Fake Out/Foul Play/Recover/Wisp
>Bulky offense: CM/Snarl/Recover/Wisp
>the rare Toxic, or Sucker Punch
Unless you're peaking around 1800 with a hyper offense team, Sableye is more than viable.
