I agree with most of this, my groupings are 1-5, 6-15, 16-30. Taking out pick 5 and lumping it in the 6-15 bracket probably underselling the importance of that pick, I think one can be distracted by the Polecs & Setterfields when it really comes down to targeting the right types and minimising the bust potential. Even at pick 4 there's been some shocking howlers, Tambling over Buddy, Toumpas over Wines/Macrae, Morton over Dangerfield/Rioli, Morabito over Cunnington etc.
The main observable change over the past decade has been the increased likelihood of landing an A grade forward in the 6-15 bracket, I think that is a better reflection of the bust potential. There was a time when clubs would make some big reaches, the Doggies spent big on Jarrod Grant & Tom Williams who would probably have gone late first round if drafted this decade.