He still has a chance considering he's already in the discussion. But when evaluating the greatest players ever, we need some time after they retired to get the idea of their entire career.
Ovechkin is probably already in the top-5 with Lemieux, Hull, Gretzky and Richard. With those four guys you can basically argue each and everyone of them as the greatest. Personally, I like Lemieux or Hull at the #1 spot the most. But I won't object the idea of putting Gretzky there or even Richard. I'm still having hard time placing OV ahead of all those four. So I think he's in the same company as them but still in the rear of the pack.
What Ovechkin needs the most right now is to have a defining playoff scoring campaign with few memorable goals there. His regular season resume is already matching up well against anyone.