Why are they lame? A better question would be why are they good. One advert has Bill Shatner in pajamas talking about how he is a shaman with some intercut clips of a tauren. What on earth is funny about that?
Then theres Mr T saying how he has a 'night-elf mohawk' when some offscreen director (the premise of which is lame as it is) tells him that he's actually a warrior. Again, where exactly is the funny there?
Reminds me of those kid's comedy shows on Childrens BBC with the canned laughter - but then again I suppose this is the demographic they are aiming for.
Lets face it, WOW adverts will be preaching to the converted mainly - existing players will see it and LOLZ because of the novelty of seeing the game on TV, non-WOW gamers will see the advert and not really understand what it's about, just 'oh thats the game that the nerds play'. Everyone else who knows nothing about gaming will just simply be 'WTF'.
I would be amazed if Shatner or Mr T played WOW...