I think mainstream games need to move away from the unnecessary or excessive sexualisation like the tiny costumes and gigantic breasts. Things like every woman in Witcher 1 have huuuge breasts, the original Tomb Raiders,
I should add I am not against sexualisation in games, or think that games should have obese, gay, and black characters- I am not a feminazi Political Correctness fanatic, far from it- but it should be used where it is appropriate or actually adds to a game. Have you seen the very first cutscene in the Saboteur with the topless dancer? It's effective at drawing you into the setting and environment. Similarly Mass Effect 1 Ashley 'sex' scene, it isn't overtly sexual and adds to the character. Would it have had the same impact if Ashley was always flashing and wearing skimpy outfits? On a similar note, think of a well-developed female character who is not overly sexualised- HL2's Alyx or TLoU's Tess for example- I wouldn't be able to take them seriously if they were flaunting 32GG breasts all the time.
Your / My second point... I am fine with DoAX's and Leisure Suit Larry's and whatnot existing as long as they're not considered as part of 'normal gaming', and I don't want them banned. Erotic films are not available, marketed or considered to be part of 'normal films'- you don't go to the cinema to see Crystal Suxxx enact her name sake for two hours do you! But you do know where to find it.
I think it should be the same for games- I don't want people to think that "normal gaming" is DoAX or LSL because it generally isn't. When I tell my colleagues that I spent all weekend playing games, I want them to think I was playing Fallout 4, TLoU, Crysis etc, just like if I said I watched films all weekend my colleagues would think I meant Die Hard, mavity, Casino Royale...
TLDR; basically what Blitzwing said.