Hi,
also for us Tesla's trade-in policy has been an issue - on two occasions.
First when trading in a Mitsubishi Outlander PHEV from March 2014 against a Model S 60D this fall. The trade-in offer arrived 2 hours before we were to pick up the new vehicle, so we had made other arrangements.
The second time when after two months, due to back problems, we had to get out of the Model S and into a Model X.
The initial trade-in offer, after only 4,000 km, was only 70,000 EUR, a whopping 23K cut on the price paid. After negotiation Tesla upped their offer by 10K, but it's still an enormous cut which we didn't expect.
So our Model X better be good, as it's going to be with us for a LONG time....