I commented on Waq yesterday, and will add to that a bit here today. I'm not actually sure that this attack 'failed.' Is AQAP really trying to kill a few anonymous strangers? Or is it looking to cut off Western civil engagement in Yemen, force greater involvement by the US (and consequent closer identification among Yemenis of Saleh and the US military)?
If the latter, there might even be greater propaganda to be had from an attack that didn't even hurt anyone -- one can assume that the US/Yemeni counterstrike causes collateral damage, which would be 'revenge' for a strike that didn't hurt anyone.
I'm no scholar of AQ, but I've always thought we make a big mistake when we think that their attacks are about us, rather than communicating/marketing to its prospects/constituents.
I would argue that you are correct in the main- it wasn't really a failure, as it generated all the response a successful (read: actually exploding) attack would- at least in the short term. I think it might fade though. After the flurry of Yemen excitement in January, temperatures cooled for a while, waxing and waning and not really picking up much steam again until this week. Had the bombs gone off- had they even been able to- it would have been a longer-term media sensation (today's elections are going to push it away for all but us obsessives). Of course, if it was probing mission, something I now doubt, it was a wild success. And in terms of tilting the balance of civil/military engagement, it will probably achieve its goals, as you very helpfully point out.
As for the last paragraph, yes, and well put, although I don't think it is entirely either/or. There is an incredible amount of parochialism when discussing AQ motivations/tactics/reason for being, and this hurts analysis and policy. But America and the West still are an enemy, even if they are far and largely unreachable. Both tactics- hurting us and growing- are intertwined, but you do offer a very useful correction to the navel-gazing hand-wringing that accompanies most discussions.
And yes: you can navel-gaze and hand-wring at the same time, both metaphorically and physically. Unless you are really uncoordinated.