Two ideas to increase efficiency, the second one a bit "out of the box":
1.) Temporary/rentable battery modules How about if one could buy a minimal size battery pack (say 30kWh), which might be all one needs for most of the year, and then be able to temporarily rent one or two additional packs/modules that could be simply added to the existing pack (a la RAM to an laptop in years gone by), if one needed to take a longer trip. At the end of the trip, the extra weight and rarely-used capacity of the two packs is returned, and a certain fee per day is charged for their use.
This would eliminate the problem of hauling around a lot of unused weight most of the time (decreasing Wh/mile), but still enable long trips to be made using the superchargers, etc. The added packs would need to be nearly identical in geometry to the "base" pack, so that their addition would not change the center of gravity, etc. But I don't think that would be a problem for Tesla's engineers if it were designed into the car from the get-go. The installation should be "plug and play" -- taking only a few minutes to do, with all of the electronics and software automatically recognizing and adjusting to the new capacity. (i.e., no special knowledge or action would be required of the user/owner/driver.)
2.) "Dynamic aerodynamic" frontal area transformation. Sorry for the awkward phrasing, but what I'm imagining (and have mentioned elsewhere) is the front of the car automatically changing to a more aerodynamic shape at higher speeds. I'm not sure how much could be gained from a simple system that made the grill area more "pointy", but if was non-trivial and could be done with some simple mechanism, it might be worth it. Of course it would all be automated -- extending above 40mph (say) and then retracting as the speed came down, 100% collapsible, etc.
Thoughts?
Is #2 that crazy? Even if not, I suspect that it might violate one regulation or another, if replacing mirrors with cameras is so controversial and difficult.
But I see 'battery module renting' far more practical and possible, and I'd love to see it offered. Besides improving overall Wh/mile efficiency, it would make the base model that much more affordable. Those who don't want to mess with renting and returning capacity would still be able to buy 60 or 90kWh versions, of course.