MGS definitely has been one with the fan-service since the beginning, but from MGS4 onwards it's gotten a lot less silly, and a lot more insidious. Mistral thankfully stays on the silly side, but the Beauty and the Beast Units have some pretty disturbing scenes where traumatised women are being incredibly objectified as they have mental breakdowns. Poor Paz in PW/GZ is an essay in herself. Props to Kojima, with Quiet he's managed to raise the bar to a whole new objectifying level. His dedication is, er, impressive.
With Quiet we have the lone female main character of the cast that firstly doesn't speak, partially out of r-e-s-p-e-c-t (legit plot reasons!), who wears a bikini 24/7 in and out of battle (plot reasons!), who has sensual showers whilst making eye contact (lotsa plot reasons) and spends a small portion of the game with her doing all of the above on display in a cage... if you have a high bond with her, she'll also do some poses for you in the chopper. (Did the whole 'her breasts = tumors' thing end up being legit in the end?)
...at least her boots are practical? I'm looking forward to her shooting grenades out of the air, at least. (Yeah, we may need a The Good, The Bad and The Quiet thread.)