So what's the big change in scouting that drafting has improved?
Did you mean to ask what scouting changes I think have impacted the drafting improvements we've seen since the early 2000s? If so, there are a few obvious ones.
1) More and better quality video of rookies. Back in the day, if you wanted to see a kid play, you had to be there or you had to send a guy with a bulky video camera to record the game in grainy standard-def footage. Now, games are far more likely to be recorded, so you can at least get broadcast footage, even if you can't get access to all the angles that were shot at multi-camera rinks. Cameras are also finally small enough that recording is easy, so it's not hard to get somebody to record games for you.
2) The use of player tracking. This is very new, and might not apply to all levels of play in all leagues, but tracking things like player speed, where they like to go on the ice, where they shoot from, how often and how far they carry the puck, where they successfully pass to, etc., is huge.
3) Combining the eye test with analytics. Neither alone is enough to make a call on a player, but as analytics started to rise in the last 2000s into the 2010s, teams had another tool in their kit to elevate a player or drop them from their lists.
4) The draft strategies and player type targeting have improved. Teams don't waste picks on goalies and unskilled players with size in the first round nearly as often now as they did two decades ago.
5) Players themselves are better. Coaching, nutrition, physical fitness, and general player skating and puckhandling skills have all vastly improved over the decades. When choosing from a better pool of players, your chances of outright blowing the pick naturally decrease.
6) The league is set up to allow more types of players to succeed. Smaller, skilled players have much better chances of being stars now than they ever did in the dead puck era. This also vastly increases your options when drafting players.
Notably, the number of NHL players drafted who hit 200, 300, 400, and 500 games played doesn't seem to change much over the years. I chalk this up to teams needing to replace roughly one key player every season, which means that, almost by default, players will get chances to succeed merely by being "good enough" to take those minutes.
Looking at the data I've gathered and counting the top-picks - picks 1 through 32 to 36 to account for teams drafting goalies - the year-over-year bust rate is:
2000 - 17 busts from 34 players
2001 - 16 busts from 36 players
2002 - 15 busts from 36 players
2003 - 8 busts from 33 players - A well above average draft class all around
2004 - 16 busts from 36 players
2005 - 16 busts from 35 players
2006 - 16 busts from 36 players
2007 - 14 busts from 32 players
2008 - 17 busts from 35 players
2009 - 14 busts from 33 players
2010 - 12 busts from 34 players
2011 - 12 busts from 32 players
2012 - 13 busts from 35 players
2013 - 10 busts from 32 players
2014 - 8 busts from 32 players
2015 - 9 busts from 33 players
Even if you want to quibble about what constitutes a bust and think that 10 years isn't enough time to catch all the busts in a draft, the trend is very clearly towards fewer wasted picks. You also see vastly fewer players taken in the early rounds who never see the NHL.
Code:
https://docs.google.com/spreadsheets/d/1UTjeav-RqH1ZKMkApHPkp6nH79l_PNkzF1lC-XXNJJc/edit?gid=1553796047#gid=1553796047
Feel free to look at the data - and dank memes - for yourself to see what trends you can find.