I'm speaking as someone who does not hold any religious faith so keep that in mind.
I find that it's a two way street that you speak about female sexualization and not that of male champs. The game does pander to a certain male gaze with a lot of its champions but as the new splashes roll out we can see them actively taking a stab at reducing the sexuality. Sona's breasts were toned down in her new one, for example. While I agree that certain female champs like Janna could use some more clothes (She even shivers! Get her a jacket!) others would lose their personal identities by being covered up. Much like Tryndamere and Braum are the strong, gruff men, Jayce the suave hero, and Varus the dark but sensitive type, we have a variety of fantasies for the women. I do think that giving female champs a body type that is curvy or hourglass does not make them sexualized. Curvy to women is ripped to men. Men aspire to be big, strong, and tough where as women aspire to be full figured, soft, and supple. Such is how our society has given the genders their roles and forms to fit.
There are exceptions, obviously, such as Ezreal being a bit of a girly boy and Quinn being fairly masculine you sometimes forget she's actually a girl, this is generally the norm. Eve and Miss Fortune, however, are the epitomes of pure, unadulterated female sexuality. They aren't just women that are there to be eye candy, they use those assets to get shit done. Fortune is notorious for being a great bounty hunter and her lore reveals she's actually quite a prude despite how racy her dress is. Eve is a sadistic hunter of the shadows, drawing in her victims before shredding them apart, all while wearing heels and leather that fits her character.
They're both femme fatales, the ultimate badass woman that not only gets stuff done but aren't afraid to be just as forward about their sex appeal as men can be. It's a typical phrase that women don't dress up for men, they dress up for themselves, and that's very true. Men will chase skirts even if they're down to the floor and they're paired with a turtleneck. Characters like MF and Eve aren't just sex fantasies for men, they're power fantasies for women. Denying that to them simply because showing skin makes you uncomfortable is just kind of selfish, since if MF needs to put a shirt on I want Varus to put some pants on.
Riot has been working away from the blatantly sexual characters such as Elise, Miss Fortune, and Eve lately with ladies like Quinn and Kalista. We need more Quinns as much as we need more Dianas, more Luxes, and more Miss Fortunes. Besides, spend a few games playing MF and you'll learn that the sexiest thing about her isn't her giant breasts, it's her confidence. She's big, she's bad, and she'll make you find yourself respawning at home~ Trying to hold fantasy characters to a standard set by books written over 2000 years ago is just well... Kinda silly.
Besides, all of these champs do have skins that are pretty covered. Hextech Janna, Waterloo Miss Fortune, and Tango Eve are some examples. Most of Sona's skins are fairly classy, honestly, just showing some cleavage which is fairly typical.
