Also, not sure if/when it will happen, but there are rumors that the SR+ will disapear in favor of LR RWD. If the price stays the same(or minor increase), this would be major.
The Model S experienced this for many years. There were a few changes that occurred:
1. Remove the lowest range model, initially the 40 kWh battery (software limited 60), then change the official 60 kWh with a 75 but software lock, then remove the 60, and so on... prices improved too.
2. This simplified production a little bit with fewer battery pack configurations.
3. This also increased range over time.
4. The higher end models would get a price cut, but not enough to come down to the previous base model's price.
My guess? SR+ is removed and now "All Teslas are long range with 300+ miles of range by default." The base price can move up from $38k to $40k, allowing Tesla to increase the battery size of the lowest trim Model 3 with RWD only. Tesla has many options to adjust pricing that will depend more on their technological improvements, which hint towards a modest energy density increase of 3-5% based on Panasonic information. If that's "all" it is, which I somehow doubt (though new tech could be limited to the S/X) given that it is called "battery day," then this relies on Tesla increasing cell count to reach this range. (I mention this variable, because it influences what Tesla can do with other trims of the 3)
If the Model 3's range is bumped up, I expect they'll still want to offer a higher trim such as a LR+ model found in the Model S lineup. Maybe this will increase the range to the 350+ miles, but I'm far less confident on this due to technological assumptions.
Beyond the range/pricing structure, I hope to see them announce details on the heat pump and its inclusion across the lineup. The biggest benefits will be if they show its impact based on ambient temperature and/or driving speed. The ambient temperature impact is well known, but still could deserve a proper unveiling to showcase cold weather benefits. I'm more curious about the impact of driving speed. Because a car creates drag in motion, and more at higher speeds, does efficiency improve with road speed from an HVAC perspective? Are they able to utilize heat in the battery pack for more cabin comfort? Can they preheat the battery pack more effectively for winter driving conditions and as a "store of heat"?
Sorry for my random post - I have a view on the SR+ getting modified (higher range). My weaker views involve the technological changes they'll announce and details around the heat pump.