One of my favourite features is the use of a form to hide the base of the flag and some of the putting surface for the player who has positioned themselves poorly.
For me, not being able to see the bottom of the flag is far more unsettling than hitting over a bunker but seeing all of the pin and green. I tend to think that most good players would feel much the same about this.
For the high handicapper, it offers no great challenge as they are primarily focused with getting it near the green and dont posses the same distance control.
Obviously it isnt a feature that could be used with the same frequency as a bunker but 2-3 times per round may be acceptable.
I really like when the form is situated short of the green creating dead ground and distorting depth perception.
Here are a couple of photos of ones I like:
1st hole Arrowtown
17th hole Harewood
18th hole Oreti sands
Where are some other good examples? I havent played it but I have heard people talk about the 4th hole on The Old Course having this feature. Photos please if you have thenm.