I wonder if the bootloader will be unlockable. I've been spoiled by Nexus devices for years and I remember how much work the Galaxy S3 I briefly owned was.
What's LG's track record like with releasing sources? Nexus devices don't count.
Looking around on forums like XDA, one sees that LG typically has different models depending on the market. The tech specs are identical, but it has more to do with carrier branding and lockdown. For instance, in markets such as the EU, LG G4 shipped with an unlockable bootloader while in the US and Asia it was not. Workarounds and custom ROMs exist, but you also see plenty of stories about bricked phones. Put simply LG simply does not have the friendliest attitude towards developers, as opposed to say HTC. They are compelled to release GPL source code for the device, but getting it to run on your device takes a bit of work.
I installed Cyanogenmod on my old S3 with minimal effort. Literally as easy as connecting to the PC via USB and running the installer. Wonder why you struggled?
What's LG's track record like with releasing sources? Nexus devices don't count.