I can't help it, I like both. I think both Azriel & Lucien can understand & care about how broken Elain is but I think Azriel has the emotional acuity necessary right now to be a considerable force in Elain's life whereas Lucien has some growing to do & that growing might well be inspired by seeing how equal-footed Feyre & Rhys are in their own relationship. I'd love to see a friendship develop between Azriel & Elain as she continues to heal - maybe a relationship if attraction develops as well. I'd also love for Azriel to get out of his routine & potentially find someone outside of their circle that feels passionately about him & challenges him. But I think he has a way to go before he realizes he deserves a chance at that & I don't think he'll get to that place until Mor tells him what she's been dealing with. I don't think that would devastate him, I think it will free him some. I'm sure it might hurt and be confusing but no more than their history has already been hurtful and confusing at times. The difference being, both of them would then be free(er) to move forward than they are now & it'll be very interesting to see where/what that is.
I didn't enjoy Feylin; from the beginning it seemed stereotypically fairytale & (gradually) so unhealthy. Feysand def pulled me more into the story on the whole. I do think both relationships were vital for every character involved, though. I think Feyre needed the experiences she had w Tamlin just as much as she needed to find Rhysand & finally step into a relationship that was healthy & loving. I'm also supremely relieved that Maas didn't just offer up a bandaid for Feylin but that you do see a lot of growth for both Feyre & Tamlin bc of how things went between the two of them. It's a slower process for Tamlin but you do see that he has some good there when his anger & ignorance stop eclipsing it. I think it's just a matter of him needing someone to stoke that for him; he was too naive and entrenched in his own person to really see Feyre as anything more than a possession that was his to mold.