Though the obvious answer for what Naruto realized is that he needs to use a kage bunshin, I think perhaps what he just figured out is that he's been looking at the problem from the wrong angle. He's been trying to make a rasengan and then add wind, perhaps the solution is to create wind and then shape it into a rasengan? This would still make it something that's extremely difficult and will take him a long time to learn without just being the same as his answer for the original rasengan. Remember when he used kage bunshin to do it it worked first time without any special training, so if its that easy he should be doing it by the next chapter. It has to be harder. The hint he got from Kakashi was "don't think of what's possible or impossible -be creative". So even if this idea is wrong I think he'll definitely surprise us with how it works.