I know this wouldn't be 'simple' - but I'm wondering if it is even possible. Looking to plug in the iPhone and control everything through the car's built in input methods (touch screen, voice etc). Finding the iPhone far far more advanced and usable compared to all the bs w/the factory installed system.
This topic has been discussed quite a bit--2 suggestions: 1. Try a search 2. Wrong forum--try the audio & electronics sub-forum
You should not even have to plug in your iPhone. You can connect it wirelessly, and then use it with your car each time you get in it, without doing anything additional. Just search the forum for iPhone and you should find all you need.
Not sure what you mean by "control everything", but I've got an aftermarket iPod adaptor and with my iPhone 4 plugged in, I can control the playlist from the "DVD" screen. The steering wheel channel change controls advance and replay songs. The big advantage of the iPod adaptor over Bluetooth is sound quality, especially much better bass response by the direct connection.