I mean no disrespect when I say this but do you have proof of Crawdaunt killing something every time it comes in? Moreover, it is extremely silly to say Crawdaunt destroys a team after a SD if it outspeeds a mon or of its weak to Aqua Jet. Well, obviously. It is no secret that of you let something set up for free, and you also lack any way to revenge kill it, you will lose to it. I can say the same for Salamence, for example. It easily sweeps if it gets a free DD, given if it has the appropriate coverage moves and given there are no ice shard users.
I won't deny Crawdaunt is a menace for bulky builds, but honestly, I'd really like replays of it 6-0ing teams on preview. And if you do find one where Daunt breaks through a Slowking + Florges + Aggron core, maybe they should have prepared better for it. The nice thing about Crawdaunt is that it has nearly the same checks as Feraligatr and Mega Sharpedo, so if you prepare for one you at least have an ok check to Daunt. Try exploring less standard sets. Creep with Florges on Adamant Crawdaunt. Run Colbur Reuniclus/Slowking/Jellicent. Maybe even run the uncommon Mega Ampharos, which is a great offensive check to it.
Here are some replays where Crawdaunt is used but doesn't destroy the opposing team.
http://replay.pokemonshowdown.com/uususpecttest-302209424
Turn 2 I get in Crawdaunt safely via a double, and I then Crabhammer the Florges putting it at 12%. Sacri had a Mence in the back, and if the EVs were correct, he could have stayed in on Slowking for another Fire Blast (his Chandy was max attack LOL), which would smoke Crawdaunt despite resisting. It then dies to Moonblast. I won't deny that if I denied its recovery later on, I probably would have won (damn speed creeping Florges). However, it seems like DD Gatr could have punched some holes in this scenario as well. So could Mamo. Are they broken as well?
His Crawdaunt makes an appearance turn 24 and kills Crobat, which I sack. It then is forced out by Ampharos and is later used as fodder. Again, it wasn't Crawdaunt's brokenness that gave Sacrifice a free kill. Switching in Gatr, again, or Sharpedo, or Mamo, or Krook all would yield similar results.
In total, the Crawdaunts dealt ~110% damage for one kill.
http://replay.pokemonshowdown.com/uususpecttest-302282025
Another replay vs a decently bulky team. It features Salamence, Whims, Nidoqueen, Stoise, Snorlax, and Honchkrow. The former five all have respectable to great bulk, so it's fair to call it a bulky team.
Right off the bat I lead Crawdaunt in case he tries to get rocks up ASAP. But, he leads Whims and I'm forced out. I fail to get Crawdaunt in safely until I use it to pick off a Mega Blastoise at 8%. Sure you can argue that I'm bad and had many opportunities to bring it in, but the fact remains that doing so via doubles is highly dangerous. Mence then forces me out and ends up cleaning after critting Umbreon.
All in all, Crawdaunt isn't this ridiculously borked fat slaying mon that people seem to be claiming it to be. We have plenty of new offensive and defensive checks, including the rise of old mons like Whimsicott, Cobalion, Heliolisk, Kyurem, M-Snow, and NP Toxicroak, and new mons like Salamence, Mega Sceptile, Mega Sharpedo (can pick off after prior damage), Zapdos, and Mega Pert. I acknowledge that these aren't ez hard counters like we all would love, but the conjunction of all these new soft to decent checks make Crawdaunt much more manageable