all of your problems will go away if you do a factory reset which is highly recommended after such a big update like android 5
If it would be so simple to fix everything by reset, everyone would do this and live happy after that :]
But about that list:
2. Yes its heat a lot... but I found out that almost EVERY new phone heat a lot, mostly those with glass.metal back... companies dont understand that today phones dont actually need such power, only better optimized apps, but instead of that they put there huge CPU's like XZ and never phones. And XZ normal temp are 60-70, I actually took pirometr from work and when playing, back panel had almost 60*C its actually hard to hold it :]
And no reset nor clean system install can fix that.
4. Actually this is only problem that could be fixed with clean installation, because its clearly problem of system(reboots)
5. that is so true. For past couple of weeks Im playing with Virtual Reality Goggles, and most of apps for that just massacre CPU and battery, and even when Im charging it, after one movie(90min) Battery is down from 70 to 20% WHEN CHARING! xD And Im using docking pins for charging because I found that they give more juice than charging from microUSB.
And in Lollipop I actually need to charge it two times per day, using only music player and browser...
And about topic... it is worth?
NO
I bought it knowing about two things that battery suck, and screen suck... its turn out that screen is awesome, but camera is tragic, especially after LP update, that now camera take worst pics quality than xperia Neo V that I lately fix to use as a Android TV(work like charm with BT mouse)
Xperia Z is amazing device but compared what you can get now for that money its plain stupidity to buy it.
Sofware on it is "shoot and miss", especially when you update to LP.
Battery is tragic no matter of OS version
Camera just suck
Cover flaps are HUGE F PAIN IN THE ARSE, when you use headphones a lot you can order new ones, or even bunch of covers, because they break up easily.
Because of heat and weird design back cover can pop up a bit, so forget about waterproof.
Without sound mods its really quiet device, especially after LP
Its HUGE fingerprint magnet....
I dont care about that, but if someone want to buy new phone, forget about xz....