1. Not really a bug, it's simply a missing feature as we haven't added support in the other UI's yet, but it's coming.
2.0/2.1 The UI does need work, but also keep in mind that the LCD UI isn't supposed to be the main UI for controlling your bulbs, so please see 1.
That said, I'm not having any issues with the saturation slider, mine is currently at 99%, but it's a little bit glitchy and imprecise if anything.
I'm not seeing any issues with the hue controls either as per your two 2.1's.
2.2 Not seeing this either.
3.0 Yes, we're aware of this, but it's not possible for us to know which colour temperature a specific bulb supports. So say Osram for example does 2,000-6,500K on their RGBW bulb, but the white/yellow bulb with colour temperature control only does 2,700-6,500K. The ZigBee standard doesn't include a means for us to tell the one from the other, so what should we do? That said, the scale seems to be a bit excessively long on the higher-end and I'll talk to the software team to see if we can cut that part and extend the lower end instead.
3.1 I'll suggest that they add this to the web UI and apps, the LCD is what it is and is again, as I said not the main UI for controlling things.
Question, did you unpair and repair your bulb after moving to R072 from whatever firmware you were on? This might help solve the issues as we've made a bunch of changes and it's possible that this is causing some problems. To unpair the bulb, go to Edit, Remove in Connected Sensors, as this will automagically reset the bulb so you don't have to do the tedious manual reset of the bulb.