Ya, soldering that tqfp44 package isn't easy. I did 8 of them once, and 7 worked. Still, I practically went blind doing it. I actually think soldering the other components is easier than through-hole. I put a tiny drop of solder flux on each component/pad and then just hold down the component with a toothpick and touch the pad with my soldering iron and it's done. Still, when they can just throw it in an oven, that's way better!
Here's a schematic of the voltage monitoring circuit. It's isolated with a linear isolator. It's also tested by my friend that made it and it works very well:
PACK_VOLTAGE is the net that is connected to an A/D pin on the microcontroller.
PACK+ is the hole where you solder a wire from the high voltage V+. GND1 is the high voltage ground. CONTROL_GND is the ground for the control, like the microcontroller. 12V1 is an isolated 12v supply that came from an isolated DC-DC. 12V1 shares it's ground with the high voltage battery pack.