The screen on the g2 is quite a bit better also.The simple fact it is much better supported. The software is crucial in a smartphone and one area where Android struggles.
I honestly don't see what makes the G2 so much better. The camera is a wash with the same sensor size and OIS apart from LG's software which ironically is much better. Battery we all know is 30% larger, but other than that the Nexus 5 is smaller and much cheaper with the same specs apart from the battery and some minor differences.