SONY's flagship is a really great device.
It's major flaws come from LARGE bezels, high price, low availability.
And sure the software isn't as powerful as TouchWiz, but it certainly looks better in stock.

The OG NOTE 1 was very innovative because it was practically the first smart/super phone with a 5+ inch display, HD resolution, large battery, and a stylus. It had a competent software soon (ICS) and a very good camera and processor for its time.

The Note 2 was like a facelift model.

The Note 3 was as innovative as the Note 1.
It was one of the first devices to bump the resolution to 1080p. It has the brightest screen out of any mobile display out there, and on-average its a very bright screen. It also draws 30-40% less battery than the N2/S4's screen. It introduced Qualcomm's new 4G antenna which draws about x10 less battery than previous offerings. It has/had the largest battery in the market. It had the fastest processor and RAM for a looong time. At the time, its camera bested the Lumia in many factors. It was also the best at video recording, and introduced 4K shooting. The camera scored in the top 2-3 spots worldwide, losing due to poor lowlight performance (an improvement from the N2's "no lowlight performance"). The body was made incredibly thin, the bezels were further shaved, and the back leather was a premium addition. The improvements made to the S Pen were great (easier to hold, accuracy, pen silo in both positions, kickstand-feature).

I don't think the Note 4 is going to be better, yet as good as the Note 3:
It'll introduce a QHD resolution which wouldn't bring any noticeable improvements to the display, but will subtract from battery life. It might even subtract from the brightness and screen latency... not good.
If it comes with the SQD 801, it won't affect battery life positively and won't perform better. Likely it will come with SQD 805 and 4GB RAM, keeping battery life same while introducing a performance increase. Apps won't really take advantage of the 64-bit architecture, or the new-improved-ART coding, or the new-material design-experience. Battery size could increase slightly, yet overall battery life is expected to drop between 10-20% of the Note 3. The overall dimensions might get physically larger, including thickness too.

I'm more looking forward to the Note 5. The "tick" of the tick-tock cycle.
It'll probably bring in new innovations in terms of:
- Apps will be more powerful, stylish and use less battery life (64-bit, ART, Material Design).
- screen glare will be vastly reduced, eliminating the need to increase brightness so much outdoors.
- power-draw improvements in all sensors should increase battery life significantly.
- phone's screen and body could be designed to be less fragile and more "tuff".
- Could be physically same as Note 3 while supporting a larger screen and battery.
- microUSB 3.0 could be introduced, a proper alternative to Lightning port (unlike N3/S5's franken-port).
- front-facing speakers could become standard.
- on-screen buttons could finally be introduced.
- a built-in kickstand could be harnessed.
- wireless charging could be factory installed.
- Note 5 could become a Nexus with updates directly from Google and Project Silver.
- screen could be curved or even bendable.
- could be slightly cheaper $500-600 instead of $650-800

At the end of the day, it'll be worth more than the sum of all its parts.