I expect another 5 -10% improvement just by switching to the 2170 cells.
Bad assumption.... they are still using 18650s.<snip>
It seems they're holding the 2170s for the Model 3, at least for now. I'd think it would take a very thorough redesign of the Model S/X pack to go to the bigger cells. Maybe it will happen after they get the Model 3/Y in production. I think Musk's recent statement that they're going to stop at 100kWh isn't a very good idea, as even the S100D is just barely capable of meeting a 4 hours plus 30 mile reserve range, @ 70 mph with no HVAC use with a brand new battery, and falls short at higher speeds, different temps with HVAC, less than 100% charge, etc. I expect other companies will introduce bigger packs as soon as they're available. At some point in the next couple of years Tesla will have to start competing with others, instead of having the field to themselves as has been the case thus far (Bolt aside). Of course, that assumes they'll still be around as an (independent) company, which I imagine depends on getting the Model 3 out on time (or at least a lot closer than they've managed in the past).