Agree 1000% with OP.
Bought MS in part because of gorgeous, information-rich, and elegantly-designed information presentation.
Have found that I use the data it presents regularly, not only to drive the car but also to learn about driving the car. (Example: Using the two trip odos to see the effects of uphill/downhill segments, addition/removal of bike racks, etc.). Even something small like the clock in the data line at IC bottom helps me to understand the changing segment behavior of my commute.
The info is also just plain interesting. For example, despite what outsiders might think, California is a fascinating place to have a prominently-visible outside thermometer. Due to our topography and micro-climates, temperature can vary up to fifty degrees during the course of an astonishingly short drive.
Finally, as a pilot, I am prone to under-stimulation, boredom, and inattention while driving, if presented with a task-poor, information-poor driving experience. That's why I have always, until now, driven a stick. The current MS IC counters the very real dangers of under-stimulation and inattention. It presents not only detailed data which I can review when it is safe to do so (trip odo numbers, energy graph, etc.) but also intuitively-rendered, grasp-in-an-instant, on-the-fly displays (orange/green power meter) which enable me to understand what the car is doing moment by- moment and improve my one-footed driving technique. (By the way, as a long-time stick driver, I find Model S's single go/slow pedal an amazing tool for mountain driving ... which we have to do here every day, even in the city.)
If v7 launches with the interface which we've glimpsed, I will be disappointed and depressed.
Will I refuse the upgrade? No, too many benefits.
Will I sue Tesla for damaging my driving experience? No, I made a conscious decision to buy a constantly-updating iPhone-with-wheels ... love the idea of updates ... just didn't think they'd pursue a 180-degree turn in the car's sophistication.
Will I be less likely to buy another Tesla? No, the car is just too amazing in other respects.
But will I consider this aspect of the car -- the great info and dazzling display aspect -- to be egregiously compromised and diminished? You bet.
Have only had my 85D for five months, but would love to become a beta tester some day.
As great as Model S is, it could be so much better with just a little more simple, clever use of the data and capabilities which it already has available. (Many great posts on this. MS owners are thoughtful people!)
As for v7 UI "improvements," a CEO and business educator friend of mine says "Strategy is largely about what you choose not to do."
Another colleague, one of the cleverest folks in all of the business realm, states that "every day will present a hundred opportunities to do something stupid. Huge success can be achieved simply by resisting the temptation."
In this case, I dearly hope that Tesla can resist, or at least soon reverse, the temptation to destroy the elegant, fascinating, and useful UI that they have worked to create.
If they feel that they must provide a simplified UI, fine, but then retain/offer the full UI as well. Offer New Coke and the Metro interface to those who would prefer it. But please leave us free to revel in our Coca-Cola Classic, Start menu, and starship MS interface!
And to posters who lecture as to why we shouldn't feel this way, please don't. We're not saying that one UI is better and more useful than another ... but merely that it's hugely more attractive, enjoyable, and more useful for us. I'm with HLR on this one.