Bobrov said the exact opposite. His appetite to be a game changer, to take the bull by the horns, be the decivisive factor on the biggest stage was one of the reason they choosed him. Remember his used car dealer speech?
I do agree to a point and see your point tho but i would frame it another way.
Slafkovsky is good when he plays "active", so creating turnover, skating with the puck, agressively forechecking.
I also think sometimes he plays "passive". So waiting for the play to develop, tendency for a too generous pass.
I agree with you that its more a matter of mindset. Hopefully the mind switch with experience and confidence.