It would be just like iPhone, all-in-one solution: a car, a stereo system, Siri-based navigation, an autopilot. Unfortunately it is not Apple who is really building the car, but the Evil Empire (http://www.youtube.com/watch?v=cdgQpa1pUUE)
I feel the same too but due to opposite reasons: They had a chance to keep the same form factor but they are going to enlarge it. They had a chance to ditch the Home but it will be there. They had a chance to fit 4.5" display but it is lousy 4" I am afraid that 4" will be the final size that won't change ever again. And 0.5" is just to little of an improvement.
Why stopping at 2015? If it quadruples every 2.5 years then it will value:
At $8000 by middle of 2017.
At $32000 by 2020
At $512000 by 2025
And by 2030 todays share (not taking future splits into account) will worth $2 Million!!!
So get on while it's cheap!!!
This is quickly going to be thing of the past unless Apples improves the screen. Then put that freaking hardware 'out' on the edge along with volume and power buttons! Don't spoil the priceless real estate.