I'll try with some thoughts.
*For the architect it is easiest to create shot value off of par 3s, as there is a fixed position on the tee box and the green is also fixed.
For example, I assume for raters, it is easy to say Cypress #16 has huge shot value.
*Off the fairway, rough, etc., my guess is that shot value correlates with hitting a great shot (whether hitting it flush and dropping right down on the flag, or hitting a running shot to match the contour of the fairway/green, that is amply rewarded. Rewarded compared to a mediocre shot. And I would add that shot value in this situation energizes the player. That is, from the perspective of the thrill of a well executed shot, and/or the thrill of standing over the shot and a heightened sense of challenge (for example, carrying the ocean as in Cypress #16 and the lake in TPC #18, or an overall setting with changing variables, sloping land, ticklish hazards, ungodly beauty, etc. such as the second shot into Augusta #13 green). For what it is worth, I would say the tee shot on TPC#18 is a higher shot value than TPC#17.
*I feel there is a strong correlation between how long it takes (either actual or perceived) between how long it takes from the moment you start your swing and the moment your ball stops -- assuming you hit a very good shot.