For me the QHD display wasn't a selling point or a deal breaker for me when considering the G3. The other device I was considering was the Xperia Z2 but I was ultimately put off the Z2 by how insistent Sony was in releasing a replacement every 6 months (and lo and behold, its being announced in a week or so). What I liked the look of about the G3 was the fact it was pretty much the only Android phone left with OIS (something I really appreciated on my HTC One and was crestfallen when they removed it from the M8) and that it had a removable battery in a body that actually looked and felt (surprisingly) premium while having a larger display in a similar sized body to other flagships.
Concerning the display, I don't feel that the 1440p resolution is a bad idea. Whether we like it or not, this is where all mobile devices (flagships atleast) will be heading towards very soon, so to be an early adopter will always have teething problems. I think that the Snapdragon 801 is not the problem here that the performance "issues" people are experiencing are down to the software and restrictions put in place to control heat (which can be disabled but frankly, LG should try and focus on improving in this area and build their phones to a slightly higher standard, I guess this is probably the reason why you can find LG's flagships for 2/3 the price of competitors after a few months, there is evidently some cost cutting going on somewhere). Also coming from the One M7, while its display was fantastic (brilliant whites, spot on colours, great viewing angles), the G3's display is really not that much worse, my observations picking up that its not as bright (but still usable outside) and the whites do look a faint greyer. But the tiny bezels on the G3 are a worth it over those small niggles for me.
As much as I have enjoyed my G3 over the last month and a half, my biggest issue with the G3 is the locked bootloader and LG's reluctance to embrace third party developer practises. Many other OEMs such as Sony, HTC and Motorola now offer bootloader unlock processes for their devices, while LG is being far from transparent regarding the issue with mixed messages coming from various channels of communication. Hopefully with the G3 being a sales success for them, this may get them to reconsider.