Honestly I like the old flag so much better. The monochrome color palette with the stripe of purple makes the most sense visually for Asexual.
To me monochrome represents a lack of color which can be represent a lack of sexual attraction and our spectrum.
White could represent the spectrum of romantic attraction since white is a mixture of all colors? That also is a perfect opposition to black since it represents the lack of color, therefore, lack of sexual attraction.