I generally don't mind sexy women in media. Hell, it's never a bad thing to have something appealing to look at.
I do, however, agree with OP about much of Flemeth's change being unnessecary.
I can understand that she's incredibly powerful and wants to look the part. I can also understand that an appealing appearance goes a long way in making people more pliant to your demands.
An attractive person WILL have an easier time getting others to do their bidding...and well, generally.
So I don't oppose to Flemeth's good looks in general, but I think it could have been handled better. The boob window was unnecessary. A longer outfit wouldn't have made her less attractive.
The thing about women like Flemeth and Meredith...etc. is that they don't need skimpy outfits to be sexy. Their power (whether physical, mental, political...etc.) is what makes these women sexy.
I found Meredith incredibly sexy, not despite but
because she was decked out in full-body armor. It screamed power.
So whenever a videogame pushes a powerful woman's cleavage and/or half-naked thigh in my face (shh you know what I mean), I feel like they're trying too hard to appeal to horny, straight, teenaged boys. (Sorry for the generalization, I'm just not sure how else to word it.)
It's just like "LOOK. BOOBS. THIGHS. SEXAY AMIRIGHT?"
And I can't help but imagine some douchebag sitting in front of the TV, grinning sleazily and high-fiving his dudebro while commenting on her various assets.
Now THAT breaks my immersion.