You're right. They're not comparable. The AHL and NHL are much stronger.
I don't care what any constantly wrong OHL scout says. Were these the same guys who said Austin Levi was an elite defensive defensemen?
I'm saying your analysis is lazy and misleading. Just because you went on HockeyDB and said "wow, look at those low stats" doesn't make Nedeljkovic a bad goalie.
There were 2.71 goals scored per team per game in the NHL last year. In the OHL there were 3.40 goals scored per team per game. You don't have to be a math major to figure out that GAA will be higher and SV% lower if there is 25% more scoring. On top of that the OHL is more polarized when it comes to the top and bottom teams, which further distorts the validity of the raw numbers.
For example: You make the argument "Nedeljkovic had a .903 SV% in the OHL Playoffs which was bad". Without context and clearly without watching a single game he played, I can see why you would reach that conclusion. The reality is that over Nedeljkovic's 1st, 2nd, and 3rd series (13 games) he compiled a 2.38 GAA and a 0.919 SV%. Which (again given the higher scoring in the OHL) is pretty damn good. More importantly, if you actually watched the games you would have seen a goalie that was dominating some of the best Junior teams in the OHL. He stole those series for Niagara.
Nedeljkovic then ran into London who had an incredible team and dominated up through the Memorial Cup. He put up a 4.25 GAA and 0.853 SV% in four games which brought down his total. If you had watched the games you would have seen a Niagara team that was completely overmatched (as was every team that played London in the Playoffs and Memorial Cup). This flogging brought down Nedeljkovic's overall numbers.
For reference, Nedeljkovic's pre-London numbers would have been 2nd best in the entire OHL Playoffs by a significant margin. These numbers would be 2nd only to Tyler Parsons (London's goalie who was playing for a powerhouse).
This, on top of Nedeljkovic's previous "OHL Goalie of the Year" award, is why he is actually a pretty strong goalie prospect and not one that is simply riding one strong WJC performance. You just have to watch and dig in a little instead of relying on the armchair HockeyDB #analysis.