Button is one of those guys who is below the average HF poster in hockey knowledge/player projections
I wouldn't say he's that bad. I actually appreciate reading his non-mainstream opinions, even though I rarely ever agree with them because it's probably a lot closer to what kinds of lists an individual scout puts together. Most central rankings are done via an average of all scouts' opinions when in reality, each of them probably have most individual players ranked 10 or more spots apart. He's just someone who has very stubborn opinions about players and tends to exaggerate about them to get his point across, but a lot of those against the grain viewpoints have turned out to be true.
For example back in the 2011 draft when Larsson/Couturier were both considered top 3 prospects, Button ranked them 7th and 8th respectively which is around where they'd go in a redraft, with Couturier going right where Button had him. He also ranked consensus second rounder Kucherov at 17 which should've been higher if anything. In 2012 he ranked consensus top 5 picks Ryan Murray at 13 and Mikhail Grigorenko at 20 (who actually fell too), which are pretty much where they'd go in a redraft. In 2014 he ranked Jake Virtanen at 43 which looks to be correct, and although he went full lovefest for guys like Sanheim at 8, Kempe at 10, Kamenev at 12 etc, all too high, these players have so far outperformed their actual draft positions. The guy is a former GM after all, he knows how scouts evaluate players.
On the flipside, he has made some mind-numblingly stupid rankings like Ryan Murphy at 4 in 2011, Matt Dumba at 2, Malcolm Subban at 8, and Matt Finn at 9 in 2012. Which explains why he's a fired GM.
For the record, he listed Marner as the #6 prospect last year and Draisaitl at the same slot the year before. Going off that, Puljujarvi is going to have a very nice season coming up.