head's up display is a nice feature to have, but it's not needed. Stuff like that should be left for Lexus since it's a costly option. People who buy Toyota are looking for affordable vehicles.
The Prius energy monitor doesn't need any changing, I've had a chance to see one and it displays all the info you need. All I can see that can be added is maybe a percentage of power left so we have an accurate reading instead of bars.