Semi-touch isn't bad or good. It just means that you have some fixed interface elements.
When you design one of these types of systems you want to make things people do all the time easy to get to. You also want those things quickly accessible to avoid having the driver get distracted. In the Lexus design they also want to be able to completely or partially disable functionality while still giving you a button to press that makes you feel like you're doing something.
The Lexus Navigation system has eight button-like objects around the screen. Design-wise that's probably good because the buttons aren't too big or too small. Seven of the buttons are functional. One of the buttons isn't really a button even though it looks like it. It's labeled "Passenger." Sometimes I press the "Passenger" button when someone is riding with me but nothing ever happens.
Many of the other buttons seem mislabeled to me. For example, to make a phone call I press the "Info" button. "Disp" is short for display I think. Why not just call it "Display"? They were able to fit the label "Passenger" on the fake button. Then there is the "Menu" button which is all about system configuration.
Anyway, of the seven real buttons I use only three: Audio, Info, and Map. I suppose the Climate button could be useful but I'm happy enough with the other temperature control buttons.
I don't find having more buttons helps with using the system at all. In fact, the seven buttons made learning the system more difficult. What happens is that you end up reading the manual because you think that phone calling would be somewhere under "Audio" or "Menu." Surprisingly, having to poke around seven separate trees of commands using mislabeled buttons doesn't make things easier or quicker.
The Lexus Navigation System has its own separate 345 page manual. That's more pages than the first Harry Potter book! Skimming through it I see that the system has a lot of hidden functionality. Mostly stuff that I'm not going to use because I won't spend the days or weeks required to learn all the features. Also, since I have to be parked to operate the Lexus Navigation System I have very little time to play with it. Google's Nexus One phone didn't even need a manual and it's capable of much more than the Lexus Navigation System.
