Sometimes girls and boys look at things differently. Girls often care about how something appeals to the senses as well as how it works. Does everything in the NXT have to be grayscale? Perhaps we can appeal to LEGO to offer a creative resource kit which might increase the NXT's appeal to girls.
The most obvious things I would include in such a kit would be
(1) pieces offered in different colors---not "girly" colors, just LEGO colors. Believe it or not, even some boys prefer color.
(2) pieces which allow for building curves---not just hard angles.
What do you think? Can you think of something that would make NXT more appealing to girls?