I agree with both these points. The problem with the feedback sandwich for me is that it seems so contrived, I immediately doubt the compliments. Also - when I'm reading for someone, I read as someone whose opinion (and way of expressing it) is trusted.
I never gave an insincere compliment in art school. Sometimes it was a stretch, but I always found something that spoke to me - color, composition, the idea I thought the artist was trying to express.
I do respect it doesn't work for everyone.