I consider the most interesting holes those that present alternative routes based upon hazard or obstacle placement, usually visually apparent before the drive, layup, or approach is struck. The solutions are only revealed over time, as one plays again and again in different winds, temperatures, and competetive situations. Heroic challenge, without safer alternative, or straight up penal, bore me. The best holes present an argument for solving problems via execution of different strategies, often based on a perception of current playing conditions.
To create such appeal there needs to be width, and cunning hazard and obstacle placement. The greens need to present surfaces that compliment good approaches or repel poorer choices and lousy execution. Recovery, generally, needs to be possible, though a fatal result can be incorporated here and there to enhance strategy dramatically at various points in the round. Additionally, predictable ground undulation usually weakens interest, instead of enhancing it.
The above is a gross over simplification, but it is meant to express that choice is important in the game as it creates interest and good controversy. The best presentation of choice and challenge make the best courses to me. I am indeed fortuante to have been on a few of them.