Well the idea of a "perfect turn" is a subjective rabbit hole. I actually do agree with TE here, a perfect turn would be a perfect execution of whatever it was you intended to do. Nothing else.
Now whether what you intended to do was the best tactical choice is another question that I'm sure could be debated hotly for another record breaking thread.
I also agree with Razie about my own preference, my own tactical choice will nearly always be to approach most all skiing situations with carving tactics in mind. I personally think that is tactically the right approach, so obviously my view is that movements conducive to carving will be more conducive to reach perfection of that goal, while other movements will detract from it. Someone who really intends to do hop turns....regardless of whether that is the best tactical decision, or the best decision for skiing nirvanna even.....whatever...to each their own...but that person's perfect turn would involve completely different movement patterns to get close to perfect hop turniness.
In the carving approach, there are arc'd turns and brushed carve turns...and neither one is more perfect then the other.... The perfect one is when you do it exactly the way you intended...either brushed or arc'd..
ps - I suggest this be another thread....