Ok guys, this is all opinionated of course, but I think that a lot of people (including myself) are a bit frustrated with the announcement of the Note 4, mainly for the lack of changes.

I put together a list comparing Note 2 to Note 3, which was a HUGE upgrade, and compared it to Note 3 to 4. As you can see, the two lists are very different when put next to each other:

note 2 vs note 3:
SD800 WAAY Faster than Exynos 1.6ghz
bigger screen
1080p vs 720p, better colors, 40% brighter
completely new features like air command, USB 3, multi vision, air gesture, able to use S-pen with capacitive buttons
from S4: IR blaster, glove mode,
better camera with new features, 4k video, slomo
Design completely new, new back, flatter front, sides that mimic a notebook
32gb storage, more ram, bigger battery,
taller, thinner, lighter; new integrated camera w/flash, cleaner look; speaker on bottom
LTE Advanced, 802.11ac
gorilla glass 3 vs gorilla glass 2
accessories: s-view cover, gear, wireless charging back, wireless s-view

note 4:
SD 805 (super fast gpu (good for 4k, better thermal design = better battery life), 2x memory bandwidth, faster cpu (15%), much better image processor, up to 300mbps let-a)
same size screen
2.5k vs 1080p, adaptive display, possibly super dimming mode (unknown), "basic" mode to get true RGB color accuracy in Note4
16mp cam with ois, 3.7mp ffc with 120 degree wide angle; side-touch “button”
Design similar; new metal sides, no stitching on back, camera is now split from flash module for heart rate sensor, like note 2, curved edged (2.5d) glass like note 2, small cuts in metal frame like iphone's antenna, black phone speaker grill, ffc moved more to corner, larger home button, edge matches color of phone's front & back
new features: 30 minute super charging, s-pen 2x sensitive, MHL3
From S5:Fingerprint reader, heart-rate sensor, ultra power-saving mode, multitasking button replaces menu button
completely new features: UV+SP02 sensors, fast-charging, bring content from one app to another with s-pen, select multiple items with s-pen like a mouse, pop-up screen, split-screen w/multiple apps, use heart rate sensor for selfies
same storage options, same RAM, battery 20 Mah more but 7.5% better; same integrated microsd/microsim module as note3, not in note 2
dimensions: narrower and thinner, but taller and heavier (N3: 5.95" x 3.12" x 0.33” in, 5.93 oz N4: 6.04" x 3.09" x 0.32” in, 6.21 oz)
speaker on back, camera and flash in 2 different components
LTE-A 300 mbps vs 150 on n3, 802.11ac with MIMO, bluetooth 4.1
same gorilla glass 3 as n3, 2.5d curved edge glass from note 2
like note 3, 3 mics, but improved in note 4; can focus on sound coming from one or two directions
accessories gear vr, Swarovski backs, montblanc pens+cases, samsung ruggedized note4 case, gear s, wireless charging back, wireless s-view
design negatives: taller, heavier, speaker on back; REMOVED: USB3, temperature & Humidity sensor

missing features: From S5: waterproof, ISOCELL BSI sensor, super-dimming unknown at this point; no dual-tone flash like iphone, speaker on back like Note2, not 64bit if snapdragon

unknown:super-dimming mode, PWM for screen dimming which was in note2 and 3, if signal is as good as note2 because note3 signal was worse
sensors (from samsung website):

Note 3:
Gesture, Accelerometer, Geo-magnetic, Gyroscope, RGB, Proximity, Barometer, Temperature & Humidity, Hall Sensor

Note 2:
Accelerometer, RGB Light, Digital Compass, Proximity, Gyro, Barometer

Note 4:
Gesture, Accelerometer, Geo-magnetic, Gyroscope, RGB,IR-LED Proximity, Barometer, Hall Sensor, Finger Scanner, UV, Heart Rate Monitoring, SpO2

I think after compiling this list, I've realized I can overlook some minor things like USB3 (even tho it was STUPID FAST!), sensors and a few other details. At the end of the day, I remember why I pick Samsung: Best-in-class screen, which is one of the biggest things about a pone, top-notch hardware, super fast, great (although sometimes useless) features, geek-friendly when it comes to expandability, removable battery/memory, customizable, etc.

That waterproof omission is going to sting tho  Really was looking forward to underwater pics without a "bag", or shower-browsing online!
The lack of USB3, Isocell sensor and speaker moved to the back are all a step back, but with all these other improvements, I'm sure you wouldn't even notice it much.