In legend, rotate arrows around their center instead of their extremity

[tvignon-artelys]

When a plot includes several arrows with different angles, due to them being rotated around their extremity rather than their center (of mass for example), they can easily overlap in the legend. See example attached.
It would make more sense to me for all markers, including arrows, to be rotated around their center of mass in the legend rather than around their extremity.