I think for a prospect it is way better to be too aggressive. Scouts do consider approach and an advanced approach gets a plus but still talented hitters with no plate discipline or a plan at the plate get drafted high because teams think they can fix that.
Longenhagen of fangraphs gets asked a ton why there isn't a grade for plate discipline and he always says that the amateur level is too different to evaluate patience.
Thus plate discipline is usually a side note on the hit tool like "hit tool plays up due to advanced approach" or vice versa "raw free swinging approach needs improvement".