I would define it by a tendency to emphasize technique over, preferably minimal, content; but fortunately usually relieved by enough exceptions, where the technique has been applied to a subject worth experiencing in itself.

Other mannerisms can become a fashion and allow to pass, eg all those milkfalls where one could argue there should be waterfalls and buildings so distorted by wide-angle lenses that it is impossible to see any craftsmanship and/or proportion.

Conversely many subjects have too much diffuse but interesting content/detail to be thus condensed, or to use such artificial drawing of attention; it is them i am arguing for and I feel need a more restrained approach to PP & for which PS is less necessary.