Agreed, appears that some of the other software is weak also. The Nav has several weak spots, a $150 Garmin has more functionality; when you set cruise it puts the cruise light on and then changes the display to read "set" so you have to toggle back-redundant and not well conceived; if you want to see what song is playing you have to page back twice vs letting the artist and title use the upper Nav screen as the song changes (when you change other settings like fan or temp. it displays on the screen) I could list several other items and I've only had my Lexus 6 weeks.
I have a Sony Walkman also and it doesn't work with the USB connection-Sony says the vehicle device must be configured "mass storage", not a Lexus option and Sony is also a Japanese Co. My Sony has Bluetooth also and I have it paired but it's not worth the effort to use the BT MP3-not nearly as seamless as Blue Tooth phone. I can't use the pairing button on the Walkman and when I do get it paired and stop for gas it doesn't reconnect-have to start over again.
It seems to me that Lexus did not test enough before production and probably didn't get much/any consumer input to make functions more "user friendly". My dealer told me that Lexus doesn't usually make changes in response to customer complaints unless it's a bug fix like my IPOD gen 5 that doesn't work....so don't hold your breath.
I've spent a fair amount of time investigating the iPod/iPhone scrolling issue when using USB. There was an improvement in the 2010 RX model during this model year. It's related to the navigation firmware. Version 3350 is "defective" and the newer version 3357 has been "fixed". When scrolling in the defective version, the top song of a list plays. In the fixed version the originally chosen song continues to play while you search the list and actually choose a new song. The fixed version is more intuitive and a method we are more familiar when using an iPod/iPhone.
If you have the "defective" version I would suggest you call corporate Lexus 1 (800) 255-3987, option 3 and explain your situation and ask that your dealership's service manager is called by corporate Lexus to let him/her know they should check back to find out when the fix maybe available.
I compared my 2010 RX to a newer 2010 RX to verify the difference, then I called Lexus. I'm not holding my breath, but I'm thinking letting them know may help.