It's a tad early in the year to judge rookies, but I'll give you my thoughts, and some up to date stats.
In goal for a very strong Chicago team taking charge for the injured Cory Crawford is rookie Antti Raanta. He's only played in 7 games, 5 of those being starts, and he compiled a very impressive 5-0-1 record with a 2.12 Goals Against Average, and a .926 Save Percentage. Pretty impressive stats, but let's not forget that the Hawks are a powerhouse team, so we'll see what happens the rest of the way.
Lots of good rookie forwards so far this year with a few surprises, and a few favorites that are coming along nicely. Here are some of the top ones so far.
(STL) Jaden Swartz: 30 Games, 8 Goals, 14 Assists, 22 points
(MTL) Alex Galchenyuk: 33 games, 9 Goals, 12 Assists, 21 Points
(COL) Nathan MacKinnon: 30 Games, 6 Goals, 12 Assists, 18 Points
(DAL) Nichushkin: 29 Games, 4 Goals, 11 Assists, 15 Points
(STL) Tarasenko: 30 Games, 9 Goals, 5 Assists, 14 Points
(FLA) Huberdeau: 32 Games: 7 Goals, 7 Assists, 14 Points
(LAK) Toffoli: 18 Games, 8 Goals, 7 Assists, 15 Points
(CAL) Monahan: 24 Games, 9 Goals, 6 Assists, 15 Points
(SAN) Hertl: 32 Games, 15 Goals, 9 Assists, 24 Points
Others to watch: (MTL) Gallagher 16 Points, (EDM) Arcobello 16 Points, (DAL) Chiasson 16 Points. While MacKinnon, and Huberdeau are suppose to be the real deal, one can't over look Tyler Toffoli's 15 points in 18 games, or Jaden Swartz's 22 points in 30 games. They are a bit ahead in the ROY voting, IMO.
There are 2 rookie defenseman who really stand out for me, and neither are Nashville rookie Seth Jones, who may end up being one of the best defenseman in the entire league some day, or Leafs Morgan Rielly who also will be a star in this league.
The sleeper of this recent crop of rookies is definitely Minnesota Wild's defenseman Jonas Brodin. Not really a rookie, as he played significant minutes last year with the Wild, but his 25+ minutes a game is remarkable for such a young player. He is slowly becoming one of the better defensive defenseman in the league. He's only got 6 Goals, and 5 Assists in 36 Games, but his minutes are what makes him one of the better rookies in my opinion.