I noticed Mickelson, of all people, didn't go for the green at TPC Boston's #4 on Sunday, so there must have been some strategic value in laying up (he did make birdie). Then again, in his post-round interview, Hoffman said he was trying to drive it in the front bunker, since he figured it would be a relatively easy up and down from there.
I agree with Michael Dugger that a good driveable par 4 should be difficult to hit and have a relatively severe penalty for failing in your effort. But then we get into that old strange question of what is an appropriately sever penalty? Other than a ball in the water, there is virtually no hazard that will deter the top 100 players on the PGA Tour. It's kind of folly to say a hole is too easy because that tiny group of players had their way with it. For most players, a deep bunker is a severe hazard, especially if the green isn't a large or easy target.