Maybe this is perverted of me, but I noticed in the new pictures that Rey's cleavage and Kylo's 'package' are being readily displayed by their new costumes. If Reylo is happening, it makes sense that SW would want to up the sexiness. They did it with Padme's more form-fitting and revealing dresses in AOTC.
I don’t think you’re being perverted at all. Let’s look at Rey and Kylo in turn here. So we have Rey:
Here, she has a tiny, form-fitting white shirt on that displays her cleavage. From the BTS shots shown at Star Wars Celebration, we know that Rey is wearing this outfit in the rain, so the fabric will presumably be clinging and potentially even slightly transparent. She’s also going to physically exert herself in this outfit (running, fighting), so it’s not unreasonable to suppose that there will be lots of heavy exhalations and sweat involved.
While she seemed almost childish and innocent in The Force Awakens, here it’s clear that she’s starting to express her sexuality and is being presented as a woman rather than a girl. And that reminds me powerfully of this quote from Rian Johnson: “It very much feels like what we all go through in adolescence, the dawning of this new chapter of our lives.” While Rian doesn’t spell it out, developing a sexuality identity is a big part of adolescence. So I absolutely think we’re seeing Rey as a sexual being now because we’re going to watch her grow up and experience attraction and desire (among other things).
Then with Kylo you have him looking much more masculine and physically dominant than we’ve seen him before. In The Force Awakens he was primped within an inch of his life and appeared almost pampered looking, whereas in The Last Jedi he has a much more naturalistic look with layers literally stripped away. While he seemed like an awkward and petulant adolescent in the Vanity Fair image of Kylo for The Force Awakens, he projects confidence and physicality now. The absence of the outer robe means we can see his legs, and that will offer him a much greater range of movement. While it’s not as obvious as it is with Rey, the trousers are quite form fitting and you’re meant to notice that this is a powerful and attractive young man rather than a scary, faceless wraith (which is pretty much how Kylo was promoted for TFA, Vanity Fair image excepted).
This stuff has actually really tickled @bastila-bae and me, since we spoke about this exact topic in an episode of Scavenger’s Hoard a few weeks ago (I’m feeling quite prophetic rn). I said I was afraid of sounding like a perv then, but they’re now making the sexualisation so blatant in the publicity images that it can only be a deliberate artistic choice.
Of course, I’m sure this has absolutely no narrative implications and will have no impact whatsoever on Kylo and Rey’s interactions when they reunite. The characters’ costumes and appearances will be entirely immaterial to how they relate to each other, since we all know that the visual element of film is pretty much irrelevant.