Would be great to have G3 specific locators; now that we have G3 Align at our disposal. It would be nice to know if another align operation (on another edge) breaks a previous G3 Alignment. My thought is that you could make the G3 version a different color; perhaps Baby Blue. (Needs to be something easy on the eyes.) It could be a different shade of green I suppose; but I think pale blue would be better. So when a surface loses G3 alignment; it switches to the typical Green color. I guess if you don't like the color idea; you could implement new labels:
G0 = Position
G1 = Tangent
G2 = G2 Curvature
G3 = G3 Curvature
So you could use these instead of the existing:
P = Position
T = Tangent
C = Curvature (G2)
? = G3
While I am on this topic of G3; I would really like to see the G3 option added to the Freeform Blend tool in the Design Package. It seems like if G3 Align is available in the Design package, that it also should get the G3 Freeform blend option as well.