Development curve like Couturier and Marchard is rare though. Going from 40 points to 80 points overnight in the middle of the 20ies is rare and uncommon. Expecting such a curve from a young player is unrealistic.
More often than not pro development happens gradually between the age of 20 and 23 over than span of 3 or 4 years. That's why personally i would like to see some form of progression from JK this season since he's now 20. If he can't break the 0.5 ppg barrier this season i would say things are not looking great (as a 3rd overall pick).