RoxaSoraXIII

I think he'll be able to dual wield, even if he returns Ven's heart to his body. Why he'll be able to dual wield after returning Ven's heart? Because of Roxas. Do you remember when you fight Roxas in KH II Final Mix? There's a reaction command that let's Sora take Roxas' Oathkeeper and Oblivion while Sora is wielding his Keyblade. He uses THREE Keyblades at once, because of Ven's heart, his own heart and because of Roxas (remember that Roxas can only dual wield because of Xion's Keyblade). So, technically, Sora will still have the power to dual wield, but I don't know if this is true... What I think what will happen when the MoM ends: Sora and Riku will complete the exam and they'll receive a lot of cool powers that are a mystery to us until the game is launched. Then, we'll be able to travel to the worlds of the Realm of Sleep, but in the Realm of Light because of plot's sake. Then we'll reach the game's final boss, we'll see the shocking ending and we'll prepare for KH3