Hmm, I don't think colour neutrality would be a huge factor. According to
this, the difference between single colour and colour neutrality is only one extra move on average.
What do you think your issue specifically is? Number of moves? How much inspection time do you use?
Have you tried Badmephisto's advanced cross video?
http://www.youtube.com/watch?v=hY_FbpdNRCQ
My average is higher than yours so I'm just throwing stuff out here... one thing I was doing recently to practice my cross (and it helps with colour neutrality as well) was that I scrambled my cube, stared at it until I figured out how to solve a cross in 8 or less moves (since it's always possible), then did the same thing for different colours/sides to avoid having to re-scramble. It might be better to re-scramble completely after each one though.