Sablelock is simply too good for the format.
Shutting down your opponent has always been a winning strategy, and Sablelock has literally no bad matchups, with the except ion of Machamp under certain conditions and with certain builds. Even Champ is easy as pie if you deny them the cards they need to get setup, which really isn't especially difficult when you Cyrus away their hand, Spray them, Judge them, and whatnot.
Sablelock can also donk easily, which is huge in this format. Anything except SPs, and even many SP builds, are extremely vulnerable to Sableye, Ambipom, Garchomp C, etc. etc.. It's fast, it's rare to get a bad start despite running few "power cards," that is, cards that give the deck speed. You'd think finesse cards such as Power Spray would make the deck slow and clunky, but in fact the deck runs extremely smoothly. It takes the most skill to play out of any true archetype right now, but if you can do it right, it's worth it.
Probably the last stop on my tirade about Sablelock's brokenness is a general note on the deck's strategy. What makes Sablelock so good is that it doesn't rely on simply outsmacking the opponent, such as a deck like Flygon, Machamp, Donphan, Kingdra, etc. etc.. Instead, Sablelock denies your opponent their setup in the earlygame, generally allowing for several prizes to be taken with Sableye or another thing that hits your opponent's active. If and when your opponent does finally manage to get a big hitter setup, you can generally either make a big hit with Honchkrow to take it down in one or two hits, or, and this is a more common situation, you can snipe around their Uxies/Azelfs, etc. with Garchomp C for your remaining prizes.
That, my friend, is why Sabelock is your play.