Is it really excessive though? Two pieces of string?
It's not a Nintendo game aimed at young children, nor has any mainline Final Fantasy been aimed at a young market.
In less than 15 seconds you can find the weirdest, most fucked up, explicit porn in existence thanks to the Internet, I hardly think a bit of skin, a glance of boob and partly visible underwear will be getting anyones heart racing.
Beside the fact there are several almost naked characters throughout the Final Fantasy series, this is very tame and nothing new.
Was it necessary? I don't think I have the right to debate that because I'd rather leave a creative mind to create what they envision, not moan about what they have created or how they should follow some set rule book of how to attempt to please everyone.
I don't know how game developers who read forums and fan sites aren't on suicide watch with the things people complain about, it's literally never ending.
Opinions obviously differ, but I think a creative project should be allowed to be created without restrictions and to the original vision, not designed by committee.
Especially in a fantasy genre, and especially in a medium such as games where 99% of what you do, is something you cannot do in life for various reasons.