See, that's not a bad idea at all! More dynamic. Needs a bit more work. I wonder if people would take to a flag that serves both the demiromantic and demisexual concepts in one design.
Hm. Aromantic, so green. One green diagonal; one purple diagonal, crossing. The crossing point would be black. Then half the flag (between the cross "arms") would be grey, the other half white.The white and grey could be divided horizontally.
Exactly Hence the horizontal division between white and grey, while the green and purple diagonals are crossing. While the black at the intersection would be those who are both. One can be aromantic while having full sexual appetite (top right quadrant), demi-sexual while having romantic feelings (top left),
Anyway. It's just an idea. Honestly, I like the first one better; it's prettier. But having both colours run parallel would imply one goes with the other, and that would be wrong.
Maybe the other option would be to have the colours in quadrant, with an horizontal grey line all the way through the middle, and vertical middle line half white, half black.
Also, I wouldn't call that the COMPLETE guide, but it has a most of the most common (and some obscure? lol) ones.