These comments are already suggesting alot of different ways to make par 3s great.
Couldn't a designer can add beauty and treachery if he's not working with a great site? Are there any great ones at Shadow Creek (I wouldn't know)?
A great one can be penal with bunkers, hazards and pits like the Postage Stamp or the par 3s at Pine Valley (? haven't played it, so I don't know exactly)
Or it can have options, like Cypress Point #16, and to a certain extent AGNC #12, where you can play a relatively safe shot or go for broke. Similarly, with a short hole surrounded by tough bunkering, you can take on a fearsome pin placement as long as you feel good about your bunker skills.
Or a good par 3 can be just plain brawny, an extreme example being that 288 yd par 3 last year in the US Open at Oakmont, where you had run-up or play short options if i recall correctly.
The surrounded by water variety like #17 at TPC are over after the first shot--psychologically challenging and memorable, for sure, but not much brain power required to get through them.