Yeah but that's so that children can use them just as well as adults. When I first sat in a Clio I was like "what the?!" because it was in the middle of my back, 2 seconds later it was raised and I thought "now that's one of the best headrest designs I have seen".
Everything else either blocks rear view or means you're moving the seat up, i.e. in the brava/o. In brava/o you lift the top 15cm of the seat up which means you get the same result as in the above but you get a bit of the seat missing!
Edit: Forgot the Mercedes folding headrests, my mistake. But they lower boot space