i'm thinking about svetlana in s2 again. i can't fathom ilya not telling her about shane, especially when s1 made it seem like she was half way there to working it out herself anyway. so again i'm left to wonder how this will impact the show.
for much of the long game ilya isolates himself and sinks further into his depression. the only person he's honest or vulnerable with is shane and even then, he's not telling shane everything. he deliberately hides how he's feeling, hides he's seeing a therapist, gets pissed when shane isn't a mind reader, however, shane is the only person he feels he can lean on, and that's not enough, not when he's struggling. shane cannot meet all of ilya's emotional needs. and that's fine. no one person can be everything to someone.
i have to assume that he's going to withdraw from svetlana in s2 out of a desire not to burden her with all his baggage. as he said in s1, he thinks he doesn't deserve her and just because she told him otherwise, doesn't mean that he's necessarily going to believe it when he's in the throws of it.
all that to say, i think that ilya's 'coming out' scene to her from the book might change to him being honest with her about his mental health. sveta is his one tie back to russia. she's the only person he still speaks to that would have known his mother and known him in the aftermath of it. so if we spend a season with him resisting help and in denial about how awful he actually feels, for him to look his oldest friend in the eye and say, i am my mother's son and that scares me - i think that would be gut wrenching.
however, more importantly, i think it would be a beautiful moment of catharsis as ilya starts to try and breakdown his emotional barriers.