The Mega Toise I am running is Bold nature with full EVs in HP and Def the rest in Spl.Atk. He gets a big enough boost to spl.atk simply by Mega evolving and the damage boost from mega launcher makes water pulse deadly, especially in the rain.
This way he retains his tanky bulk and high defense but can strike back unlike any other wall in the game I've seen. He does need recovery so running a sleep/talk set isn't bad as far as his move set goes. Though you 100% need Water Pulse on him with the buff to it the Gen and the extra buff from Mega Launcher he wrecks shop with it.
The other Pulse moves I'd suggest are either Aura Sphere or Dark Pulse, Dragon Pulse is nice but only super effective against dragons and your better off with Ice Beam for a wider coverage if you want him to take down dragons. He really needs a better recovery move then rest, however he is limited in this regard though if you don't want to run Sleep/Talk I'd suggest running a little utility such as Rapid Spin and Toxic for clearing hazards and wearing down other tanks (be careful of Aegislash he is immune to both Spin and Toxic).
Your move set? --- XL GT: Hellkite87 FC: 4339-3900-5649