Actually, I do mean the characters. I understand how important they both are to the canon. RT lets both of them be very abusive to IY in the manga. In the Kind Boy chapter Kagome's friends even come to the conclusion that Kagome is the person in the relationship who controls the other with violence contrary to what they had believed. Shadowsweaver1 has Kagome and Sesshoumaru comment on this in Vying for Dominance. Sesshoumaru gets Kagome to admit that they are both bullies because they like to beat up on Inuyasha for the fun of it.

Kagome and Sesshoumaru do change over the course of the manga. Kagome only uses the osuwari command three times after Kikyou dies. When Sesshoumaru throws away Tenseiga in the Meidou arc, he is willing to risk his life to save his brother (of course maybe he just does not want Naraku to kill him.)