If I have one complaint at this point, it's that the whole thing with Mamoru being all "I don't want to die" and "I don't want to be disposed of," feels a bit familiar, since it's more or less the same issues that everyone have been struggling with for awhile. I am curious as to why Mamoru is being targeted when, as they said, he doesn't fit any of the "problematic" profiles.

But I'm willing to see where they go with it! Maria, Saki, and Satoru are still pretty great as characters. I wish they gave Mamoru a little bit more screentime, especially with his drawing thing/Mamoru as artist, but he's been a bit out of the picture since way back in ep 8.
I do like their use of the weakest link idea, since the natural consequence of that is that there's always a weakest link/most vulnerable, until eventually you're just left with the one on the top (Saki). And I think the meeting with the head of the ethics committee was super cool for making them less villainous/more understandable (before the stuff with Mamoru), and introducing a kind of long-term goal/endpoint for Saki herself.

The memory erasure thing is totally heartbreaking and really interesting. I do like the presence - haunting, as Saki puts it - that Shun still keeps over Saki. It's a really interesting idea, and Maria/the show puts her/its finger neatly on that strength of Saki's and her constant dedication to the truth.

From here, I'm predicting Mamoru will be killed, and Maria will snap and turn into a fiend (hence finally getting the explication for K), fulfilling that hint from way early series that she'll be responsible for the deaths of many. Or maybe Mamoru snaps, and Maria in protecting him is the one that catalyzes it.
I hope to be proven wrong, since I always like when my expectations are surpassed.

I'll admit the characters were probably the last thing to win me over to the show compared to everything else but I'm quite satisfied with them at this point. Saki has a lot of nuance to her personality and she's developed quite a bit over the story, even if part of that was offscreen during the 2 year timeskip. Maria is developing quite well too, even if it's probably not going to end well for her as Saturos mentioned. Her opinions contrasting with Saki wanting to find out the truth has been really neat to see since it stems from her wanting to protect Mamoru. We also see that she is still under more stress because of this since she's still macking on Saki like a Bonobo when other characters have stopped doing this. The show has done a good job of defining the characters by how they act and react to situations instead of going out of it's way to define each one as "x" archetype like many series do.