5. Backup cameras. They're legally required in some jurisdictions (so I heard), and genuinely contribute to safety, but they require a screen. Once the screen is there, there's both less space for buttons and a virtual hook for features.
There is so much opportunity for better regulation, without making more numerous regulations.
I already have a screen showing what radio station is playing, and one on the dash telling me where to go. If a screen is required for a backup camera, just combine it. If I'm reversing I probably don't need the satnav anyway, whereas if I'm reversing or using satnav I probably do need other functions which just means you need an even bigger screen so you can fit everything on.