In ESPN's prospect rankings, Shestyorkin was the 10th ranked goalie, but two of the goalies in the top 10 are already NHL goalies, Murray and Vasilevskiy. He's really 8th of non-NHL goalies. Pronman made a rankings of the top 10 goalie prospects in January, and Shestyorkin wasn't in the top 10. He also made a list a year ago, and Shestyorkin wasn't in the top ten, instead he listed him 13th. So Shestyorkin has went in the opinion of Pronman from 13th to 10th in one year, but he didn't give any honorable mentions or next five in his January rankings, so we don't know where he had him ranked in January. In the poll section of HF, Shestyorkin was ranked the 7th best goalie prospect, but that section didn't count Murray and Vasilevskiy, so he really would've been 9th if you are using criteria that counts those two.
Buchnevich was 14th in Pronman's prospect rankings last August. In his January rankings, Buchnevich was 7th. Now he's ranked 30th. In the January rankings, Buchnevich was only a few weeks into his time with SKA, and Pronman was not downgrading him for his time with SKA. Now that he finished the season with SKA, it seems clear that Pronman is downgrading him for his time with SKA. We all know what happened at SKA. They didn't want to give him consistent top 9 ice time for a lot of the time, and he was playing injured in the playoffs. I don't think its anything to be worried about. As long as AV doesn't treat Buch like SKA did, and actually wants to invest in Buchnevich's development as a hockey player, he should produce.
SKA is a complete developmental nightmare. Shestyorkin is right now going through the same things as Buch did. Last year he was the best goalie in the second best league in Russia, breaking single season goalie records in that league, and this season SKA has him as the back up, not even their starter. They'd rather start a guy who tried to play in the NHL, but wasn't good enough. Its not just Rangers prospects that they don't give much playing time. Devils 5th rounder from 2016 Yegor Rykov should've been a mid 2015 round draft pick. He has showcased incredible talent playing in the MHL, VHL and for Russia in international competitions, but he has only played 13 career KHL games, and even this season they aren't giving him a bigger role than he had last season. It should come as no surprise that Buchnevich dropped when he moved to a team that does a terrible job with young Russian players.