I am still curious as to what the Part 3 reveal will be. By the time Part 3 comes around everyone will have already seen the new release body shape with the new better looking nose. What is it that is being held back for the Part 3 reveal?
I know I might be beating a dead bush here but I personally think that Part 3 will be all about the interior. The "spaceship" is the final piece of the puzzle imho.
I think you're right that, by the time Reveal 3 rolls around, most of us who follow Tesla closely will already be very familiar with the final exterior, based on the rate at which Model 3 spy shots are rolling in already. As Tesla iterates on the release candidates and starts using more production parts (e.g. the conspicuously-missing charge-port reflector), we should assemble a pretty good idea of what the final car will look like, including color, wheel, and potentially other options.
Similarly, though, I think the growing encyclopedia of spy shots will also give us a pretty good idea of what the final interior will look like -- and I am expecting it to look more or less like what we've already seen. Is it possible that Tesla has built some super-secret RC with the "real" (spaceship?) interior hidden inside their testing facilities, and it will never see the light of day until the final reveal? Sure... but I'm not counting on it.
My expectation is that the final reveal (which may also turn out to be one-in-the-same with the "Model 3 Delivery Event", if it ends up happening in July) will focus more on the
experiential aspects of owning a Model 3, with an emphasis on software.
Yes, they will give a brief overview of the production exterior, interior, and specs (drivetrains, battery sizes, estimated EPA ranges, 0-60 times), and talk a lot about Autopilot and FSD... but I also think they will cover Model 3's necessarily unique UI for the center screen, and explain (to our satisfaction, or not) how this UI gives us everything we need to: (a) drive the car, (b) let the car drive us, and (c) allow the car to drive others on the Tesla Network. (In other words: why "we won't care" that there's no traditional information console.)
They will also talk about the new delivery centers and streamlined delivery process, including where and when we can watch orientation-type videos in advance of delivery, how we will always be able to access these same videos (and interactive tutorials?) right on the car's center screen, and how Tesla will continue to update this instructional library along with its regular OTA software updates.
At the end, they'll let us know that the Model 3 Configurator is / will soon be open to the public, that reservation-holders will be invited to configure based on reservation time and ownership status... aaaaand that will be it. Elon (and perhaps some lucky Tesla/SpaceX employee/investor/honoree, driving the first production Model 3) will exit stage left.
Subsequently, some of us will flock to TMC to complain about the lack of "spaceship" controls, and how the final car didn't match up with Elon Tweets (x), (y) and (z). Some of us will decide that this car (as it currently exists) truly isn't the one they want, and cancel our reservations... but the rest of us will just cross another day off on our calendars.