Not really.
It is kind of amateurish for him to keep using clones, but he took a very complex technique and dumbed it down to the point that pretty much anybody can use it. Before, the Ransengan involved a complex series of steps that were hard to master. However, with a clone, Naruto was able to make it much easier. Furthermore, his use of clones allowed him to complete his father's unfinished technique by adding chakra nature to the mix. This was impossible for Minato, Kakashi, and Jiraiya, but naruto perfected it in a matter of days.
Inventing a technique=/= learning a technique.
Jman dumbed it down for him considerably.
And then he dumbed it down even further for konohamaru.
And as for the speed he learned it well. Like I already said learning=/= inventing.
As for how quick he learned frs he used clones. All the knowledge from the clones goes back to the user effectively cutting training time equal to the amount of clones.
If he dispersed said clones then made a new set the new set has all the knowledge he collected from the previous set.
Even though he perfected it within days considering the amount of clones he made multiplied by the amount of sets made and the amount of days....technically it took him years.
Let's say 1000 clones over 3 days with a new set each day
1000 clones x 1000 clones x 1000 clones x 3 = 1000^3 x 3= 3,000,000,000 days worth of knowledge in 3 days. That's several hundred years.
