Hey - I am the researcher on WR and hopefully I can shed a little light on this.
We did a ton of research talking to players, and at the end of the day, we think these models are going to be a big improvement, while still staying true to our Champions.
One of the things that we spent a lot of time really talking through is figuring out what exactly it means to be attractive, sexy, beautiful, etc and how things like exposure fit into those definitions. A lot of times these words are used interchangeably, so we really wanted to clarify what all these things mean, both to us as designers, artists, researchers, etc as well as to our players.
Attractive and sexy are things that players like - there will always be room for niche characters and non-traditional ideas of beauty, but for the most part attractive and sexy is something that players like in their characters. When you look at the new model of Janna for instance, she is beautiful and attractive. When players talked about the old splash, a lot players felt that her outfit didn't really make sense for her character. The issue wasn't the exposure, it was the fact that it didn't make sense for her and her power fantasy. An easy way to think about it, is would Janna "The Storm's Fury" rock the outfit in her original splash when she was waking up for a day of battling on summoners rift? To most of the players we talked to, that felt like a stretch.
When you look at another champion like Ahri for instance, things are almost unchanged outside of updated textures and small tweaks. Her outfit looks like something that she herself would choose when going into battle, which makes the entire package feel good to players.
That is the core of what we were going for with the new models - our art team wanted to make Champions that kicked ass and felt like they themselves were a part of Runeterra, rather than a character we drew, dressed, and posed.