Juan Martin Del Potro I think you meant. And DelPo is a better player than Raonic IMO. He has had a lot of wrist and injury issues though. He EARNED his USO title the hard way. Also had Fed on the ropes a couple times @ RG a few years ago. But conditioning cost him in those matches. But he has improved in that dept. Just has been unlucky with some injuries.Yes Raonic can, if Juan Michael del Potro can win a Major so can he.
As for Genie, she's still a full year away from hitting her stride. Chris Everet said it herself, she got taken to the woodshed on her first final against Billie Jean King.
Still worry about Genie's power quotient though. Look at the players she lost to at the majors this year - all had more power than her. Against the big hitters her time is taken away. Part of that is her court-positioning. She is stubborn with her court positioning and refuses to give up the baseline. But I think that can be traced back to her power-quotient. The reason she wants to take the ball so early is because lacks the power to hit through the court that some of the bigger hitters have. So could she take a step or two back? Sure, but the added power she generates may be negated by the territory she gives up. It is a balancing act.