Some shaving of pubic hair is necessary depending upon the cut of your poser and how much of a bush you have. Trimming it below where your poser rides on your abdomen so that it dosen't show and create a distraction is probably sufficient. Some guys may shave it all off due to the total removal of body hair which is standard practice in competition, but it really isn't necessary. I like having some hair "down there" and not looking so "boyish" otherwise. Apart from competition, however, trimming your public hair also has the advantage of making your package look bigger since it isn't covered by a heavy bush. Looking at yourself in the mirror says it all. How much you trim is a matter of personal taste - keeping it thick but trimmed, leaving a shadow, or going for a shape (square patch, triangle, chevron, etc.). Shaving your balls is an option, too, and something that a lok of guys do when trimming pubes.
OK, I have to admit I would like to see that. Some guys look good completely shaved. I've found that I do not. I'm better keeping things neatly trimmed with just my balls smooth.
Matt, have you noticed that keeping your pubic hair shaved makes your cock and balls look bigger? It would certainly make them more noticeable.
Some posing suits from the 1999 Pro World Cup:
Orville Burke at the 2002 Mr. Olympia contest in his posers: