First off let me say that having average wants and needs makes me...well, average. However, this does have it's advantages. For example, when an up and coming car company might want to know what most people would find desirable in their vehicles.
So here's my list. I hope someone capable of making decisions is listening.
1) It's my understanding that the model S has limited space for "things". The Model X is clearly Tesla's family version of the sedan and they need to know that while it may not look as "clean", people need storage spaces within reach for their "stuff".
2) Front and rear A/C. It's already hot in Florida and it's gonna get worse each year.
3) 12V DC outlet plugs. At least 2. We can supply our own splitters if needed.
4) Seats that fold down flat and/or remove and install easily. They are currently a freakin nightmare in most models.
Lastly. I know this one is a stretch but it would probably boost sales through the roof.
A small efficient range extender. Be it a Fuel cell, standard 1-2 cylinder gas engine or whatever.
Just enough to get you that extra 20-40 miles in a pinch.
Build that. They will all come.