Yea, LO Bisharp is the best. Iron Head has much more usability now that fairies exist, and the Dark-type & Knock Off buffs just made Bisharp the Defiant mon of choice (in the other hand, we have Tornadus, who got shafted from losing Flying Gem :(). With LO, Bisharp can essentially OHKO all Intimidate mons barring Scrafty and Mawile (after it mega evolves) with its STAB moves.
You can make a lot of good offensive cores with Bisharp, since Defiant and Dark-type (plus priority) offense is so good in XY Doubles. Bisharp + Kangaskhan is one of the more notable ones. Bisharp discourages Intimidate users from hindering Kangaskhan. Bisharp also eliminates pesky Ghost- and some Steel-types that gives La Madre some trouble (mons like Aegislash, Jirachi, Jellicent). Augment this core with a Pokemon that can handle Heatran and Fighting-types (Gyarados, Jellicent, Azumarill, Chandelure @ Air Balloon, HP Ground Latios, Dragonite / Salamence) and you're good to go ;d