What version did you play? There was a bug where the routes got haywired at the end, but this is fixed in the meantime. What you see as implied is not exactly correct. For instance, if you are on the Beta route you´ll see Sunny and Marcus kissing and flirting in her room at the end of day 10. If you are on the Alpha or diplomat (Sis and some other girl focus) routes you will see that Marcus tries to flirt, but gets shot down by Sunny, who prefers reading one of her books.Looks like NTR is the primary focus here. Played through both main routes, "Alpha" and "Beta", and the only differences i could notice are that the MC imposes himself a little bit more in the Alpha route, but if there's a impeding NTR scene he just kindly leaves and let them do their own thing, which implies that the scene still happens, it just so happens off-screen unlike "Beta" routes, which kinda contradicts itself with previous decisions, since if you're playing as a dominant role you would impose yourself way more.
You must be registered to see the linkswhich still in version 0.1, shows exactly how a dominant role would act out perfectly, while here it kinda half-asses it.
As for DIK, I will look into it what is done differently there to compare.