A/C and heating for vault area is a must. For camping in the bed as well as for keeping your dogs alive when our shopping etc. Helps for perishable goods and even if you do have a fridge in the back too. Could use the solar power option when stationary to keep the car cool whilst parked.
Slow Remote driving is also a good idea. I'd like to see through the cameras whilst doing so, and in general have access to all the cameras internally as well and through the app at all times. Could possibly get away without using a spotter offroad then.
Needs a straight in front of bumper camera, and real time terrain mapping for offroad which it can display under a transparent vehicle as it drives over. So you can see where your tyres will end up, a projected tyre path would be handy too.
That follows into getting the terrain response to setup the suspension and power to the wheels that have the most grip. Technically, it could use the cameras to automatically identify the ground type, traction coefficient etc for the ground surface and configure everything itself, even with path recommendations etc. to avoid bottoming out or slipping in a rut etc. Sort of like a off-road autopilot.
Then the tyres need to have a auto deflate system for airing down to a preset pressure. This can be triggered internally, and would allow for much better range and performance in sand and mud offroad. It should also remind you to air up when you are on a sealed or hard road again, and limit your top speed until the tyres are inflated again. A CTIS would be awesome, but probably out of budget. A decent size air tank would be good, or use the spare at overpressure to get the tyres refilled faster.
A hitch summon feature that lowers the vehicle and aligns it to hitch up would be good, as well as a trailer reversing aid. Obviously the autopilot should be optimised for using the trailer, for cornering, sway, braking, lane changes, and wind etc. Some reommendations for towing, like best speed for towing in wind or up hill would also help. A dual channel brake controller (left-right) linked into the anti sway should also be onboard.
Another thing it really needs is a haptic feedback accelerator pedal. That means when active it should always "recommend" the best throttle position for the task at hand by offering less pedal resistance in the optimal range, to either improve range on road, or traction off road. (Lots of nannies, but then everyone drive like a pro!)
Pass through storage or a slide down rear window would be nice, but I don't think either will be easy to do given the cover rolling up under the bed, and the front of the tray being angled to follow the reclining angle of the back seats. Access between cab would be a nice option for pets or camping though.
In general rail mounted seats would be awesome with the two main front seats being to swivel. So long some of the seats a rail mounted they can be moved or removed and replaced with other Tesla accessories. That would make it possible to sit and with a popup table in the the front cab, to eat, have a meeting, or use as a mobile office. Ideal for when you have a camper on the back. Easy foldflat seat backrests might even allow a cab bed arrangement too. At least for kids.
Recovery points, winch and simple points to mount a bull bar would be nice. Along with some extra relay outputs for accessories and lights that can be controlled by the screen and app. Some antenna mounting points and ways the route cables inside wouldn't hurt either.
The 230V output should be rated for at least 30A, or around 7-10kW like the Rivian. Two of those would be even better, but I'd love to see car to car charging as well, as an option, for service vehicles and serious overlanders. There should be a socket in the bed and cab for it. A in bed charging connector would also be interesting for range extender packs or geny. A extra solar input for external solar would also be another good option. You could then use the CT to power your RV or cabin, further reducing fossil use.
I think a full length external heavy duty rail system should be offered on the back for low profile racks. That way long items could be transported on the back instead of in the tray (probably 10-11ft long)
The bed should really come with a drawer option that can maybe be also used as the ramp. That way you load the stuff onto the drawer from any side, tie it on and lift it in electrically. That tailgate ramp is much too steep to be useful. If you attach the tailgate to the drawer you could technically have a extending bed setup for longer loads.
A spot to mount internal accessories with dedicated power would also be good to have. For things like CB radios, trip computers, docket printers etc...in a perfect would they'd have a API and a connection to run this all off the main screen. A cooled glovebox is easy to do, along with plenty of door storage to keep things organised in a work truck.
A foam void fill package to make it amphibious with a hitch mounted electric outboard....