Best character made by kishi.

[NarutoSamaKama]

Naruto, Nagato, Itachi, Kakashi, and Hinata.

 

[EL GENIO]

Pain , Kisame and Sasori

 

[Flawž]

Their portrayals, how they play their roles, how "human" they are, how they fit and live in the crafted world and society by author.

I can make small analysis for the listes characters because there are too many factors what makes a character "well written" in their own rights; but that would be time consuming.

Judging by that, I can tell why you like Lee, Neji and etc.

Well, everyone has their own opinion on what makes a character well written or not. My point is that Overall, The characters i listed ablove are well written in all aspects.

Development
Flaws
Thier importance
Dialogue
etc.

(Minus minato, dunno what i was thinking)