Yes, the visibility toggle is a good option, but I think you missed the point about the “compact” mode. This would be a mode used by individuals who prioritize efficiency in information presentation (and ability to access items without scrolling), and who do not care about the latest fads in UI visual design (large margins/padding, rounded corners, etc.). Call it “Ugly” mode if you want, but please make it more usable for power-users! 
Why not solicit user feedback about how to make the compact mode more compact? In addition to reducing padding and margins (which seems to be the only change introduced in the beta version of compact mode), how about:
- Using fonts with smaller aspect ratio (to improve horizontal information density)?
- Using an autofill icon instead of a text button?
- Eliminating unnecessary hint text (or providing an option to disable hint text)?
- Eliminating some unnecessary labels (like the redundant “Website” label)?
