I bought a thermostat about a year ago and I've been disappointed too. The marketing I read and a couple people I knew that worked there implied that new features were in the pipeline but since I've installed it I haven't seen a single substantive improvement in the experience.
As for future promised features, they're like campaign promises. Nothing to bet big on.
I have two sets of furnace/AC for my house and two Nest thermostats. My wifi access point when I installed it was downstairs, about 10 feet from the downstairs thermostat with nothing but air between the AP and the thermostat (I moved the AP around a bit too). The unit would not connect even though the upstairs unit connected without issue.
Worse, every time I tried to connect it, it would make me re"type" my wifi password. My password is around 30 characters long and contains a mixture of letters, numbers, and symbols. Entering a password on a Nest thermostat is absolutely terrible, which I kind of expect, and which is okay if you only have to do it ONCE. But I was trying to troubleshoot a problem with wifi and it wouldn't remember the password because it wasn't connecting... I ended up changing my wifi password temporarily until I could get it to connect and update, hoping the update would fix whatever the problem was.
That said, now that they're installed and connecting, they're fine, I guess. But the "wow" factor is pretty much over for me, and with what I've heard about the smoke alarms, I doubt I'll be buying another Nest product.
Another issue I have is that I can only schedule temps. Auto-away seems to recognize in about an hour that I've left for work, but Away state never shows on the schedule. I leave for work at the same time very morning, I'd like the thermostat to tell me when it thinks I've left so I can adjust it to the correct time and not heat/cool the house for an hour before it realizes I'm gone.
These are minor things, but I paid literally 10x as much as a regular programmable thermostat, I expect a premium experience.
Would be nice to have optional different displays too. Seems like a silly thing, I know, but it would be nice if I could just setup the 'normal' display to show outside temp without having to go to the menu.
As I mentioned above, I want better and longer access to data so that I can do real comparisons like year over year data. Not just 10 days ago which is really stupid.
And how about a more stable app as well that doesn't crash?
We typically leave the thermostat at 79 or 80, and even then that's several hundred a month in AC.
Why? Well, Florida. And the fact that I'm on the 2nd floor of a multi-tenant building with poor insulation. The struggle is real