I do think that the easiest players to scout are forwards playing in the CHL. Why?
1) The skills that translate best for forwards are very visible. Great skating/shooting/puck handling. For dmen things like positioning, consistency, first pass, etc. are more important, but these skills stand out way less and are much harder to measure/predict
2) As for CHL vs. Europe, in Europe a player is never going to dominate, they're just going to look decent or not, because they're playing against men. But does that mean they'll be a solid role player, or a star? Tough to say. In the CHL guys are playing against their peers, and against tonnes of other players who will be drafted high. If a player is clearly dominating the best of his CHL peers at 17/18, chances are he'll still be dominating those same peers when he's in his 20s, and thus he'll be a very good NHLer
If a forward seems like the best player in the draft, chances are very good that you're looking at a future star. If a dman seems like the best player in the draft, there's more of a risk that you're just getting a good, but not great player. If a goalie seems like the best player in the draft, chances are you're about to make a terrible pick.
Purely by numbers you'd think that 2 forwards would go 1st overall for every 1 dman that goes 1st overall, but because dmen are harder to scout/project, that's not how it goes. Look at all the 1st overall picks since the year 2000:
2010 - Taylor Hall (forward)
2009 - John Tavares (forward)
2008 - Steven Stamkos (forward)
2007 - Patrick Kane (forward)
2006 - Erik Johnson (dman) <- Staal/Toews/Backstrom/Kessel went 2/3/4/5
2005 - Sidney Crosby (forward)
2004 - Alex Ovechkin (forward)
2003 - MAF (goalie) <-Eric Staal went 2nd
2002 - Rick Nash (forward)
2001 - Ilya Kovalchuk (forward)
2000 - Rick DiPietro (goalie) <- Heatley and Gaborik went 2/3
Dmen really have not been popular 1st overall picks since the mid 90s, and we haven't seen a 1st overall forward come close to busting since Patrik Stefan (that was an attrocious draft year, and even still the next 2 picks were both forwards, Daniel and Henrik Sedin, and they turned out great). Meanwhile all the non-forwards picked are basically looking like poor to awful choices vs. the forwards they were picked over.