Though I agree 100% that a great 1080P display would be better for battery life and performance, tests have already shown that the N4 display is a new more efficient tech that is actually 17% more efficient than the N3 (not G3) display. That is impressive and battery life tests so far confirm this.
LG went the cheap route though and used older tech with Qhd on the G3 and has resulted in a hotter running, weak contrasted, battery draining device- in spite of the "Pixie Dust" crowd reports
The N4 display is twice as efficient as the G3 display. Based on the battery life weight of a display on a device, this fits the 1.5/2.0 hours better battery life.
The N3 battery lasts 1.5/2.0 hours longer than the G3 for
screen on time and the Note 4 is reported to last the same to slightly better than the N3. The N4's GPU has to work more, so the 17% efficiency over the N3 is offset.
Still, YES on a 1080p display, since would result in at least 1.5 more hours of battery life. Based on the new lower power tech of the OLED design on the N4 (per Displaymate), 1.5 is probably conservative.
Added: Anecdotal perspective- I compared the G3 and N4 at Best Buy. The G3 display feels very warm to hot (depending on load), but the N4 is barely warm. Also, comparing the displays side by side truly shows how weak IMO the G3 display really is. G3 fans would be best served to NOT compare the displays, since ignorance is bliss
Unlike the G3, no halos around text and no gosh awful contrast or viewing angle issues either.