IPS LCD is enough to warrant the change.
I hate AMOLED on phones, and the Galaxy Nexus was a bad one in my opinion.
Plus, Roms like Paranoid Android and Revolt flash RGB and Gamma settings to calibrate colors and makes the Screen noticeably better in my opinion.
LTE works on my Nexus 4 too, but I'm in Canada.
Pentile isn't that big of a deal according to all the users here. The problem with the GNex and in general Google phones is that they don't calibrate. I've seen the Nexus S, GNex and they're totally off. It's a crazy purple glow they have. I'm not even sure how you call that white.
On the other hand I've seen a properly calibrated Nexus S after Voodoo color got released. It looks gorgeous. The GNex has the potential to be beautiful too with Franco's color tweaks or other kernels. You just gotta go do it. The SGS3 uses essentially the same screen except Samsung went and tweaked it a bit.
The 720p screen on the Nexus 4 is nice for clear text, but if you hold it up against even an Optimus G, it pales in comparison. Compared to the awesome HTC One X, and it's a total piece of crap. It's like iPhone 4 vs iPhone 5 once they went to a calibrated screen. Night and day difference.
I think if all screens were calibrated they could look nice. Just a point of comparison. Nexus S pentile WVGA vs. SGS2 SAMOLED+ WVGA, SGS2 wins. But when you calibrate the Nexus S, it blows the SGS2 out of the water. Too bad the SGS2 is stymied by Exynos and the devs haven't found a way to calibrate the screen yet, but it'd look beautiful as a Plus screen.
Similarly, the Nexus 4 needs some actual gamma tuning. The Paranoid Android screen settings look decent, but I don't think it's all the way there yet. The screen's still washed out like my TN panel at work.