Not exactly sure this thread belongs here, but since i feel a bit nostalgic...
Tarasenko and Kuznetsov were both Top5 talents, everyone acknowledged that, so here is the pure Russian factor (compare to Burmistrov, who went 8th). Also that year Zaitsev went undrafted because of the Russian factor. You could add Panarin also here, but he wasn't that obvious, for example I doubted that he will succeed, also size was a very big deal back then.
Kucherov's case is about Russian factor too, but also he was heavily underrated: while he was great in the MHL in his draft season, I can't remember him appearing in any rating before the U18 WJC that year. And even after that people were talking that he is undersized (160 lbs at that time) and that his points were inflated by Grigorenko. Fun fact: 2 years after his draft, in 2013 he was voted #5 Lightning prospects here on Hfboards behind Drouin, Vasilevskiy, Killorn and Connolly, so you can see that even at this point people didn't view him as elite talent.
Buchnevich wasn't considered a first-round talent back then, but probably without the Russian factor he could've gone in the second round. And yes, he also was lightweight (I think he was 160 lbs too, iirc).
Kaprizov's issue was that in his draft year he didn't dominate yet, he was just good and promising and also got injured at the U18 WJC. Also a bit of Russian factor, as people remembered that he was #1 KHL draft pick. And yes, he was a bit small too.