Use face's normal for adjusting movement gizmo rotation in face mode.

[darkhog]

So it will be easier to move faces along their normal vector without distorting the entire mode. Related, if block has been rotated, add an ability to use a local pivot instead of aligning gizmos to the world.

[darkhog]

Okay, I now realize that I wasn't all that clear in the OP, however it's late, I'm tired, and due to me not being a native speaker, my English suffers because of my tiredness, lol. Anyway, thought to add a picture. Basically I want to move the face outlined in green along its normal vector (the blue line), with the movement and rotation gizmo being aligned to it: