Yeah its going to be a project I'll work on over time.
The problem I'll have in collecting the data is quality of defensemen. For example, Mark Streit (9th rounder) is clearly a more renown defensemen than, say, Cam Barker (top 10 pick). But Cam Barker still played 310 NHL games. Looking at the data for 2004, Cam is considered a successful defensemen since he's among the defensemen who actually played a single NHL game (34 of the drafted 84 defensemen). Even if playing 50 games is considered successful, he's only among 23 defensemen in that class. And obviously with defensemen, quality cannot equal points because there's really defensive defensemen that are successful.
But I can assure you that throughout the history of the draft (I'll stick to 20 years probably), the picks in the top 10 will likely have a better
success rate than those outside, by which I mean those picks out of all picks. Or those picks out of all within the category.
He's where I can see a flaw in the data: Top 10 draftees will be mostly forward players. The actual top 10 defenseman selected might occupy the first 60 picks (spanning 2 rounds) whereas the top 10 forwards of a draft will easily occupy the first round.
But we'll see. I hope you've bought yourself some crow... in case you get hungry