What ‘soldering’ exactly are you talking about? The device isn’t soldered together; most of the components on the motherboard are however.
Soldering small components (i.e. WiFi card, bluetooth card, amplifier, power supply, RAM) is fine. The only of those components that you would realistically be upgrading is the RAM, and the device is only designed to handle 16GB, so if you had 8 there isn’t a huge point in upgrading after the fact. I can’t remember if the SSD is soldered in place, but it wasn’t in the prototypes.
When it comes to repairability, having those small components soldered to the motherboard is a good idea because if you believe one is failing, it could be the fault of the motherboard. Even if the Bluetooth card seems to be the issue, it’s smarter to just replace the whole thing than the small component and hope that solves the problem.
The battery, case, kickstand, and screen are not soldered in place, and the device is actually repairable. Like I said, if you can get new components, and be able to remove the screen without breaking it, you can repair them on your own.
@mirv did a teardown of the V here, maybe @nawthor can open that link up for everybody to see.
(@nawthor’s notes: the link is open to everyone at Trust level 2, which only requires reading. The reason these old prototype topics are limited is exactly so that people won’t accidentally stumble upon them before they understand what is going on.