I do hope we ally with or take her over. I like her style of control, loyal, dumb smile, making thralls into "good girls", which is a style of control we haven't seen a lot so far in a game that has a lot of different styles of control. Would be nice for MC to be able to control some women in that way.
I am of the same opinion. One thing I love about Lustful Sin is the variety of different types of mind control that can be used on the girls. We got the main character "pink eye" ability that turns them into obedient sluts. Lily's empty eye ability that makes them completely mindless (and can also be used for petplay). That mind control visor which turns the girls into obedient drones. Violet's ability to possess the girls, and so much more.
However, even with all these different kinds of control, Yurie's power do feel unique and different.
From what we have seen so far from brainwashed Rin, it looks like Yurie's style of control allows Rin to retain some indepent thought. When interacting with her mistress Rin repeatly asks her questions, shows the ability to plan, and can work without direct orders to please her mistress. In additon Rin seems to be able to act like her non-brainwashed self, so she must retain both her knowlege and memories while under Yurie's control.
Also it is kind of scary how Rin refers to her friends, calling them "those girls" rather than "her friends" when with Yurie. So when she is first controlled she refers to Eri as annoying, and later says that Eri's body belongs to Yurie. Does Rin no longer care about her old friends at all? Is she everything she is doing as Yurie's spy just an act? Does some part of her still care for Eri, Ai, and Hana, or has Yurie wiped those feelings from her mind?
Regardless I am looking forward to the upcoming patches to see how this plot point develops.