Having female MC doesn't mean you can't introduce standard sex properly
No it doesn't...But it does mean that you (male playing female) will probably wind up sucking that cock./facepalm.
Glamour char will be female. That does not necessarily mean that there wont be "dicks" involved.
Many guys play these games as a roleplay and put themselves into the role of the MC. They make their decisions based on what they would like to see happen.
How many guys or folks outside the LBGTQ community are interested in roleplaying a cock sucker?
And sure he will be expanding his target audience to include the other half of the population (namely women), But how many women do you know who spend their money on Pornography?
If DS was really smart he would allow you to choose which sex you played as and allow the story to play out that way.
Then he could even include gay themes if the user chooses to pursue the men in the game or ignore them and just go for the women.
A TRUE OPEN WORLD sexual experience that would allow him to take the sex anywhere he wanted.
That would be the smart move...But again it takes a lot of work on his part and he has never really showed to be the type that does the hard thing when he can get away with the easy route.