As we saw Sasuke wants his brothers eyes to Go 100% on naruto
This is what madara wants ...
1- a possibility that could happen is that madara is going to kill sasuke when he got the eyes to get the EMS that was his plan..
2- ( or Sasuke is way too powerfull with itachi's eyes even stronger then itachi himself with his own eyes and then kills madara but i dont see that happening )
3- he is going to use sasuke in the 4th world war and then takes his eyes afterwards but i dont see that happening either...
Feel free to comment and to tell us what you think that will happen when he gets the eyes of itachi