He was considered as a good prospect, but not an elite one, also the Russian/KHL factor and also that he was something like at least 20 lb smaller at that time.
Yeah, in all fairness though, it happens that hockey players develop a lot in short time, and that a lot of things come together.
There is a discrepancy between what works in the KHL and what works in the NHL. The first time I saw Buchnevich after he was drafted, he had several bad habits in his game on the ice. His coach in Russia had called him out for being lazy. And he isn't "super talented".
I think there only is 20 Russians in the NHL, and they produce a lot of good players every year. A lot of the good players that they do produce, do not end up with long NHL careers. If I am a betting man -- I don't think I pick Buchnevich in the top 45 at least. Buch ended up being drafted 75 overall... And I am fairly certain that I am a lot more inclined to drafts Russians than the avg Joe. So its not a big fall.
But after that, Buchnevich had a really strong year last season and improved on a regular basis.
Now when I see him, he is very very dilligent and smart on the ice. That is a remarkable improvement over how good he was at the time he was drafted to be perfectly honest. He has definitely gone from being a player in the more like the Zherdev mold to a player in like the Loui Eriksson mold.
So of course, the Russian factor has played a part in him dropping. But I think the biggest reason is that he just have improved a lot lately.