That there's a way that Sora have the ability of Synch Blade WITHOUT Ventus's heart.Okay,just imagine of Sora can use one Keyblade at hand without Ven's heart because of the bonds from his friends that makes his hearts stronger and let the Keyblade choose him.Okay,then when Sora becomes a Heartless while his Nobodies was created,which is face does not like Ven.When his nobody grows a heart like Xemnas said,then if Sora's nobody return back to Sora,Sora can able to use Two Keyblades at a time without Ven's heart,one heart for his and one heart for his nobody's feelings.So yeah,i think that Sora can use Synch Blade without Ven with that way,but this is just my opinion,to be precise.So,what are your thoughts?...

Yeah he should be able to...Probably

yup..i'm quite agree with you

Roxas uses Sora and Ven's Keyblads same as with Sora so Roxas (the nobody in this case) would not help him with dual wielding.

So the plan is basically:

 

Step One: Have Sora split into a Heartless and Nobody and again but this time without Ven's heart interfering so that his Nobody is a true Nobody.  

 

Step Two: Let his Nobody grow a heart strong enough so that he can attain his own Keyblade.

 

Step Three: Tell said Nobody that his sole purpose in life was to become his own person just long enough so he can get a Keyblade and then he would have to forfeit his life and assimilate into another being just to give him a second Keyblade.

 

Step Four: ?????

 

Step Five: Profit. 

 

Seems foolproof.