If someone starts off inside a plane, passes through a hole and ends up on the outside of the plane screaming as they plunge to their doom, does it really matter whether they're blown or sucked?
The point is, why should we care? If the bomb only kills a couple of people but fails to bring down the plane, then it is no worse than the mayhem a lone gunman could cause on the ground. In fact he could probably cause more death and economic chaos by blowing himself up in an airport choke point.
The reality is that well-funded, competent terrorists who are knowledgeable enough to plan a mission like this and suicidal enough to carry it out are really, really rare. Rare enough that I would be happy if we reverted to 1999 level passenger screening as my chances of sitting next to a laptop/shoe/underwear bomber would still be less than the probability of getting stung to death by bees on the way to the airport.