First off, this is a fantastic phone, so I realize that some at Sprint are rolling their eyes right now.
However, there's always room for improvement, and Sprint and LG could change some things.
The battery life in any smartphone could be better. Maybe the fact that I'm always getting 1-2 bars (out of 6) has something to do with that? I've not had a dropped call yet, and Sprint Data seems fast, but the network coverage could be stronger. Also, LG and Sprint should take a close look at which bloatware could be axed. The G3 is supposedly far better than the G2 in this regard, but continue the process of making devices more "Nexus-like."
The notifications screen is a continual annoyance. From top to bottom, notifications take up too much room, especially for those who want the font to be a little larger than normal. It'd be nice if it were cleaner. I don't want a mini remote control showing up there, nor the volume settings, nor shortcuts for items that would otherwise take only 2-3 swipes to change. Keep it simple. The Wifi-Calling app automatically puts a 2 line notification, all the time. When I'm entering text from the on-screen keyboard, a notification appears. There are too many needless notifications, and they take up too much room from top to bottom (too many lines).
Quick Remote, the programmable / universal remote app is VERY cool, but the mini-version doesn't show the ones I've created, for some reason. Seems like a bug. I've designed 3 remotes, but only 2 show in the mini-version (on the notifications screen). Why not the 3rd? When I deleted the first 2, I still didn't get remote #3 appearing. Besides, I should have control on if I want the mini-remotes to appear, and which remotes. It was like the phone chose my first 2 attempts, without asking or giving me a way to change that.
Why duplicate Sprint versions of browser and email, plus Google ones? That confused my spouse.
My hearing is pretty good, and yet calls on the highest setting are kinda quiet when things are noisy. Some of us are paranoid about pressing our skulls against a cell phone, and yet don't want to use speakerphone, and don't always have a headset handy. And WHY are speakers on the back? This is 2014.
There is always two email apps; one for Gmail and the other for exchange/POP/IMAP emails.
Same goes for the browser.
This is really a LG feedback since Sprint doesn't make phones.
Responsibility for the UI is primarily LG's, but Sprint has some control, and their input can affect the G4.
And Sprint does have some control over the G3's UI. The Sprint LG G3 notification screen is different from Verizon, AT&T, etc. Sprint nixed the brightness slider, but included the volume slider. Sprint also prevents us from disabling it. How do we know that? Most carriers have the G3 show both of those sliders by default, but let customers disable either or both. Sprint should do that, too, IMO.
As for the plain email and browser apps, I realize that it helps Sprint to do that. It simplifies customer support. Your support rep knows that you have that standard, plain app. The steps to getting you on the right path are going to be the same for all users, and they won't change, since the app will never change its UI. There are no complicating factors, like email being filtered, or cookies being blocked. So, yeah, that part makes sense. It doesn't have to do with Exchange or IMAP/POP, though.
*shrug* its a start