That's simply wrong.
It can't show enough by itself to make a definite judgment, but you can certainly note a number of key factors in the decision:
1) has the player physically matured, become stronger and can translate that on ice, everything from skating to upper body strength in the corners
2) has the player improved their skill package, skating (balance, not just speed), shooting, passing
3) has the player improved their hockey IQ
Take those observations and combine them with the player's history and you're in position to make a better decision.
The eyeball test can give you a general sense as a fan, do they look like they belong? Are they being pushed around, caught out of position, rushing everything? Or are they under control and dominating play when they're on the ice?