Tesla currently displays the energy efficiency in watt hours. Everyone who has owned a gas car and used to miles per gallon has it ingrained in their head that the HIGHER the number, the better the efficiency. However, using watt hours is the inverse and so it's just the opposite.
The LOWER the number the more efficient.
Moreover, when we want to quickly calculate how many miles we are adding or what we think our real range would be, it is FAR easier to multiply the typical Miles/KWH by the number of KWH we think we will be using then to try to figure it out from watt hours/mile where you both have to inverse the number and convert watt hours to KWH.
I would like to suggest that we have the OPTION to display Miles/KWH in place of Watts/Mile. I think it would be easy for Tesla to see what people prefer and this option would be easy.
I also don't see why we can't display BOTH the battery percentage and the estimated miles left. These numbers easily fit on the screen and sometimes it's useful to see both.