David,
I agree that there is plenty of room to go left of the bunker, but hitting it there presents a whole different set of issues. Let's say I don't want to take on the bunker with driver and hit a good 3-wood left. Now I've got 35--65 yards, a half-shot that many golfers don't like, especially off of a tight fairway. It is going to be hard to get any spin on the ball, so holding the green is an issue. Putting is not really an option, especially if the pin is left, the large mound guards the entire left side of the green. I guess if the pin is on the right side you might be able to putt to the right bank and hope it kicks off the slope and comes back to the green...I'm not used to this kind of "long-range" putting, I wonder if any of the Aussies or Tom think this is a viable option?
However, if the pin is left and the back slope really works to feed the ball back (I don't see how the ball can stay on that slope) maybe I would be better off going long left, so that I have the shortest possible shot to hit the back slope. But as Kevin points out, now if you miss your tee shot right, you are guaranteed to end up in the bunker and you can say good-bye to par.
To me, this comes down to your philosophy on how to attack short par 4's. I hate screwing up these holes with my tee shot, so I would almost always choose a club that will leave me just short of the trap and try to make birdie with a good full wedge and my putter, and expect to make par almost every time. Now when it comes to the 12th hole, which we'll see later, my decision will be different because that hole sets up so much better for a fade, my natural shot, because the landing area seems much deeper than the "slot" that Hole 4 shows me. The second bunker is there to catch any ball that does not fade back to the 4th green. On 12, there is more friendly-looking slope that will help feed the ball back, and you'll maybe miss the green on the left. It is so cool that there are two somewhat similar driveable par 4's that lead me to different decisions!