It isn't as much as one note characters as much as the character haven't been followed up at all. Take Hinata. Her shy and gentle nature is her natural nature. Because her family that was supposed to love her degraded her as trash because she had no natural talent...she had no confidence, but Naruto helped her change. Problem is...after getting beat by Neji she hasn't even appeared in the story except to use her Byakugan while looking for Sasuke, and getting one shotted (manga) by Pain. During the war the Second Division basically didn't exist just like the Fifth division (we saw litterally nothing of these two divisions fighting). Because Hinata was in the second division...we didn't see her do anything. Helping aim the Mind Body Transfer tech has been the biggest thing she has done since reassuring Naruto that he was strong just before he fought Neji :'(...
Hinata actually has a descent ammount of character to her, but she doesn't appear enough, and she doesn't show any new techniques. It is dissapointing considering she is one of my favorite characters lol.
In your example, Shikamaru has had more developement compared to many K11 members. While his background is more of a regular person. He shows constant growth up until the war. He starts off as a lazy kid. After the Chunin exams he shows his intellect and becomes a Chunin, and shows nefound leadership with the Sasuke retrieval arc. Further on we see grief in Shikimaru when Asuma is killed and we see new variations to the shadow mimic technique in that he can use it to stab people now. In the war he acts as the second in command to Gaara's division, and is seen stopping not only Kinkaku, but Obito as well (untill he is almost ghetto stomped by the Gedo Mazo). Overall, Shikamaru has actually shown growth as a person and as a Shinobi ^.^...
Basically the more screnetime a character has, the more we notice their personality growth and more techniques!