I don't want to seem like I'm bashing on Riot's writers, because they often do a stellar job when it comes to writing amazing lines and interactions (my favorites being Swain, Yorick, Rakan & Xayah, and, most recently, Pantheon). Yet the writing for Senna felt very lacking to me, especially the way she interacts with Lucian.
I get the idea behind their interactions: they both feel super akwkard after being apart for so long, and don't really know what to say to each other, just because they both changed so much and have a lot of doubts on their mind. That really makes sense, and I fully support the idea.
However, I don't think that "awkward" should mean "literally all of their interactions are (somewhat cringy) jokes". Don't get me wrong - funny banter is a very natural and important part of a romantic relationship which makes it more lively, human and realistic. But there should be other things besides just banter. I expected Senna and Lucian to be more mature in their interactions, but instead they sound like a pair of corny teenagers aka Rakan & Xayah 2.0, which I really disliked. It felt baffling hearing them just joking as if ever nothing happened. Once again, I am NOT against joking - them being all dark and brooding about everything would've been just as bad. But I expected at least a 50/50 split of jokes/more serious interactions. Those are two deeply traumatized people, and that fact should still be visible even behind their awkward attempts to break the ice.
I wrote a couple of additional interactions between Lucian and Senna to better illustrate my point. I don't claim to be a good writer myself, but I just wanted to give an example of lines I would've expected to hear from them. For instance, I had an idea that Senna can barely feel the physical world anymore, like losing the ability to sense smells, temperature, taste, etc; and Lucian would describe these for her. It would show how she's not really alive and not really dead, and give us a reason why Lucian feels conflicted about her, while also being an insight into Senna's current state.
> "Your hands are... cold."
"I feel warm. That's what matters."
>"When we find this monster, I--"
"Lucian. We don't have to think about him anymore. We can think about us."
>"Senna? Is... is everything alright?"
"Oh? O-oh. Sorry. Was I staring?"
"Um... kind of, yeah."
"I just... I almost forgot what you looked like. I want to make sure I didn't."
>"What does it smell like?"
"The air here."
"Uh... well... you know. Dirt, dust, salt... and the delightful hint of rot."