I just read this on CNN and wanted to post it here, but Yannis beat me too it.
I think what they mean with "dull" is the fact that the engine is so quiet and the ride is somewhat isolated. Granted, most buyers in this class may want this, but there are also a ton of buyers who would like to hear the engine as it adds character to the car.
My family at one point owned a 1998 Nissan Cefiro Elite which had a 2.0 V6
VQ engine. This engine was so smooth and silent, it made the good-looking Cefiro drive like a sleeping pill. You couldn't hear the engine, even at higher RPM's. Some people like this stuff, others don't. I'm part of the crowd who want excitement behind the wheel, who want to hear the engine, who want to feel the road through the steering wheel etc.
The LS is no doubt a technological achievement, but Lexus has created this car for the crowd who want isolation from the outside world. Think about it. All the German and British brands have a high degree of sporting character in their cars; not the Lexus. When you drive the European competitors and then drive an LS afterwards, of course the car will appear a little dull.
