The Galaxy Note 4 was the LAST true Note phone. It had the IR Blaster, replaceable battery, a real home button, same screen resolution as the note 8, same fast charging as the Note 8, better camera,
The Note 4 was a cool phone but the build quality was average (compared), mine creaked, I had to get the screen replaced due to burn.
It's a good thing the battery was replaceable as they didn't last very long.
My friends still use theirs to this day and the friend I sold my Note 4 to, also still uses it still, but the battery has been replaced a few times.
As for photo quality, the Note 8 is ahead in my opinion.
I've already compared the Note 8 photos to my photos from my Note 7, 5 and 4 and even 3.
That is of course if that's what you meant by better camera, there are other factors like focusing speed, shooting speed, low light ability etc..
I just don't see where the Note 4 is better in any metric apart from higher megapixels.
The Note 4 also had a smaller work area, the screen looks tiny compared to the Note 8, the pen wasn't as feature rich, the internal memory was smaller, the fingerprint reader was much much more clumsy, Touchwiz needed more tweaking, it had a lower screen resolution with lower dpi, less battery life with a similar battery, slower network speed etc...
The note 4 did have the IR blaster I guess, I did find that useful at times.