It would be interesting but I don't think that information density necessarily makes a good interface.

As a personal pet peeve example, developers love to cram a search bar (or browser tabs) into the top of the window. It's more dense but it's also harder to use and drag the window.

True. More accurately, it's a combination of high density, judicial allocation of whitespace, and layouts that have been thought through. The 2000s versions of OS X were better in those regards too, though.