As someone who has been fortunate to play the course quite a few times, I can confidently say there are no duds period. You learn something new on every hole every play, and that's part of what makes the Downs so great.
As for 17, MacKenzie has made an incredible hole out of incredibly tough terrain. It provides the player with several options, which can change dramatically depending on the wind. One can go for the green, leave it 20 yards short, 50 yards short, 80 yards short, 100-130 yards short (the most popular safe play), or down on the bottom level 150-170 yards short (I've played to all of those options). Any of the in-betweens will funnel the ball into one of these areas or down into the rough on the left side. Uncommitted swings and indecision lead to nothing but trouble. From the tee this hole is all about choosing an option and committing to it. The boldness of the terrain demands it and makes it unlike any other hole I've ever played. To top it off, the wind is usually howling stronger into your face here than on any other spot on the course.
It also tends to get in your head several holes ahead of time. 310 of the most frightening yards of golf indeed.
All that said, it is a members' course after all, and is playable for any level of player so long as they give it some thought and respect. The arrogant and ignorant pay the highest prices here.