Hair direction and angle with vertex groups

Hello,
I'm new in Blender (and in 3D generally), I use this awesome software for a month now.
I always have to comb again the hair on my object because the mesh editing spoils it so I've got an idea to prevent this: I think we could control the basic direction and angle of the hair with vertex groups and with the hair editing we could override it (copy the values from the vertex groups and make it unique).

Example for hair angle:
Weight 0 = 90° (as default value)
Weight 1.0 = 0°

Example for the hair direction:
Weight 0 = 0°
Weight 1.0 = 360°
or
Weight 0 = X (as default value)
Weight 0.125 = XY (45°)
Weight 0.25 = Y
Weight 0.5 = -X
Weight 0.75 = -Y
Weight 1.0 = X