If you've already got an LG G1 OLED TV living at the heart of your entertainment hub, we'd like to assume that you're more than happy with what it offers. Even though the G4 does indeed make some big improvements, that doesn't make the G1 a waste of space.
That being said, the G4 offers much better viewing during the day and in a well-lit room thanks to the advancements in panel technology, particularly peak brightness levels with MLA. This is the driving force to upgrade in our opinion, and if you aren't always going to use your TV in a darker room, then it certainly warrants an upgrade if your G1 doesn't cut it any longer.