The car is great. If my lease was up, I'd likely buy another. The UI, however, is not so great, and this has been commented on many times (mostly around the release of 7.0). While I'm glad they updated the media player UI, they ignored a lot of other things that I think most owners would have rated more important.
Elon hinted at further improvements for 8.1, but maybe you've already forgotten about the major improvements he promised in 7.1, which never materialized? Lots of promises that either show up very late, or not at all.
I'm glad that they continue to improve the auto pilot. I'm not so happy that the improvements come with degradation of other features. And I'm particularly unhappy with the fact that the improvements come at the cost of almost everything else!
The Tesla is arguably the most advanced car in existence, yet the iPhone app is embarrassingly outdated, the maps lack basic features that 5 year old Garmins have, they refuse to integrate mobile phones (aside from bluetooth), and in general, they just don't seem to care what the current customers want; seems to be much more about attracting new customers, having the fastest 0-60 times, useless features like pulling itself into a garage, etc. If they're not interested in fixing the problems we bring up, then I'd prefer them just not ask in the first place. And while I've never had another car gain features while I owned it, I also never had one lose features.
Apple released their maps app after Tesla. It was pretty awful at first, universally ridiculed. However, since the release, they've made enormous strides and they're now competing pretty well with Google, beating them in some areas. Customers complained, Apple wanted a product worthy of their name, they listened, and they delivered. Tesla, in that same time, has done almost nothing with the maps. My maps are still rarely updated, still give bad directions, still can't add in stops, still draw slowly, still don't give you route options, etc. I'll be impressed when I don't need to constantly pull out my phone because the Tesla either does something to slowly, doesn't do it well, or frequently, can't do it at all.