Pain invasion arc was only about 40 chapters, whereas Tale of Jiraiya the Gallant was about 15 chapters, so in all Pain was developed, given a proper backstory, provided characterization to the main character, given his main motivation and resolved all within 55 chapters. That is an author who knows how to not waste the reader's time on nonsense drivel. If this were a specific author, not to be named, it would have lasted 10 years and across 4 major arcs where a backstory wasn't given, main motivation still not understood, no characterization for the main character and the character is still not resolved.
His backstory being from the Hidden Rain Village where it was the battle grounds where the great nations waged war in, then his fight between Jiraya and Pain where Jiraya met his end, then him being the catalyst for Naruto to understand that the world wasn't so black and white as Naruto thought it was, and much more where all great for me so I give Pain a 10/10 as a villain. The ending with the talk no jutsu could have been executed better in terms of providing a better reason for Nagato to trust Naruto with his dreams but I am not going to blame Kishi for that since it's hard to check every box in any character.