The thing that bothers me most about the scanner is that there's absolutely no scale reference to give you any indication how far away or how fast you or anything else are. It's like those distance markers that fly along the sides of your screen when you're in supercruise. What do those lines mean when I'm travelling at 10c, or 100c? Are they 1ls? 10ls each? No indication whatsoever. I didn't even know the scanner had a default range of 500m, or that changing it did anything noteworthy, or that the yellow marker below it was the zoom indicator. Everything scales based on your relative velocity but you get nothing to keep track of the scaling with, to the effect that all of this information becomes totally meaningless variables.
It's like reading a road map that gives the grid scale in kilometres, but doesn't tell you how many kilometres each grid represents. The scanner's basically useless to me, I don't look to it for anything except basic position and motion information that I use to build a mental image of the space around my ship. Just seems unnecessarily obtuse for the sake of saving one or two numbers worth of HUD space.