My take. Tinordi was a bad pick, and took up two picks actually. By the time of his D+2, I could already see he would bust. Bummer that so many good players were drafted after Jared. We could have had shots at TWO of them.
Beaulieu lacked hockey IQ. He hasn't made it anywhere despite strong straight-line skating when young. A risk at 18OA but the offensive potential maybe justified the pick at that rank. Can't win 'em all.
McCarron was a lost opportunity but our mistake was trying to force him into the C role. He had good potential for a 3rd line winger, IMO.
Fleury and Mete were mid round picks and never made it anywhere. I'm not too disappointed, again it's part of the draft game.
Tinordi wasn't a terrible pick at the time he was drafted but the league got faster. His "good for a big man" speed pretty quickly became too slow for the game. Lefebvre told him he had to fight if he wanted to have any chance, he got concussed by career goons with no NHL upside, and his game fell off a cliff. His skills mostly came with caveats, good skater for a big guy, good fighter for a skilled player... In his first camp he could defend, but he wasn't good with the puck.
McCarron needed skills coaches in his first year and only got them 3 or 4 years in. He also needed to concentrate on his skills and not worry much about gooning it up. He was a major reach, too.
Mete needed to go to the AHL and learn to shoot, among other things. His lack of size and physicality was always going to be a problem but he might have had hope with more offence and a shot. His development got trashed by going to the NHL and leaning on Weber for all the physical play and shots.
Leblanc was the poster boy for regression with the habs. He got the worst of Lefebvre in all ways and got worse and less motivated every year he was here. Hard to say if there was real upside but he should have been able to play third line, he could survive in that role his first year.
Lekhonen was fine, but he didn't play in the AHL. Andrighetto was as good as can be expected for where he was picked, and he survived Hamilton. Brook was disappointing in the AHL.
In most of the no-successful-prospects years there just weren't that many high picks. The earlier firsts were OK, the later ones mostly disappointed but weren't really bad for their spot, and there were some injuries. There were a lot of career AHL/KHLers including some late picks that did more than you would normally expect from a late pick. The lack of 2nds and 3rds hurt.
I don't think there was a single problem, it was a combination. There weren't many picks in the early rounds, picks were so so, AHL development stunk, NHL development was bad, there wasn't a lot of skill development or outside coaching at any level... Most of these items have been addressed.