You may bail out right, leaving you with a more difficult approach, but the proper way to play Merion's fifth is to draw the ball off the tee for maximum distance (507 from the rear tee) and fade the ball into the green--often off of a hook lie. The alternative approach when the green is firm is to carry the bunker short and right of the green to feed the ball onto the green. Pin position is key in determining the approach shot. So if you choose BB because it requires you to shape two different shots, I think you are misjudging Merion's 5th because that is the best way to play the hole.
Merion's 5th is also more sophisticated in this regard: challenging the creek gives you a flat lie. If you are in the middle to the right side of the fairway you have the hook like when you need to hit a fade. The ball striking requirement is much higher. BB has an aerial approach requirement.
There's a lot more going on at Merion than BB.
Wayne,
You'd be hard pressed to find someone who loves Merion as much as me (I coached the Haverford School golf team there which included Tug Maude and John Sawin) but I'm not going down on the 5th at BB without a fight. Both are world class par 4's, but that's what makes this comparison so much fun.
While the "proper way" is to hit a draw off the tee at Merion, you don't have to hit that shot... you can hit the ball anywhere from the middle of the fairway to the right rough and still have no problem getting home in two. That's not the case at BB where the diagonal cross bunker demands an accurate tee shot and the woods on the left punish a bailout away from the long way over the bunker. Go too far left and it becomes a par 5. Go too far right and your in the woods. Come up short and you are in the cross bunker which is basically like a waste area ala PV. IMHO, the tee shot is more strategic and demanding at BB vs. Merion.
The approach shot at BB is also demanding. Even from the middle of the fairway, you have a blind putting surface and have to hit a draw with some height to a back left pin. Anything near the front of the green is also an issue as it becomes difficult to stop the ball on the elevated green. Add in an extremely deep front right bunker (which glares at you) and a blind back bunker and you start to see how exacting the shot can be. Line, shape, distance and spin must all be spot on.
The approach at Merion is similarly exacting, but in a much different way. The front right bunker hides some of the putting surface from the right side of the fairway, but most of the green complex is visible. Because of the steep pitch in the green, I usually aim for the front right corner just over that bunker with a short to mid-iron and hope to end up somewhere on the surface and preferably below the hole. I know some people that think the hardest pin is front right (at the top of the pitch)... I couldn't disagree more. While it would be difficult to get close to, at least you'd probably be putting uphill towards the hole and it takes the creek out of play. I'd like to see the pros play a back left pin with a firm green. In closing, while they are much closer than the tee shots, I still think BB is a more precise approach but I do like the ground game option/variables at Merion.
The green is hands down to Merion and one that has to be seen to be believed.. At US Open speeds you will see 4 putts by some of the top players. BB has a subtle green with some speed coming down the hill which fooled players including Tiger during the final round. However, when taking a look at the hole in its entirety, I still think BB gets the nod.
In regards to the back tees... I have seen the new tee at Merion and it is intimidating. However, most players will rarely play there and I have also heard that Currier has added a new back tee to BB which will bring the cross bunker even more into play. I don't think either tee really adds much to the discussion other than making these holes play more for the pros like the normal tips do for us mere mortals.
Looking forward to Round 2, Mr. Morrison...