Why is there increasingly such an avid interest in sex and romance around these parts?
It's supposed to be a space opera, not a dating simulator.
To be fair, ME's gameplay - cover based shooting against medium amounts of wave enemies followed by the occasional boss fight - is a gameplay mechanic that has been ground into dust by the industry.
Not that there's anything inherently wrong with that, but almost nothing about ME's gameplay has broken anything close to new ground.
Weaving character storylines into a modular, changeable cinematic story with adult themes that pervades multiple games without canonical endings, however, is less common. The video game industry has always tried to claim it has the same storytelling gravitas of the movie industry (it certainly makes more money than the movie industry), but video games have always taken either a puritanical or puerile attitude towards sex and interpersonal relationships - either clutching their pearls and fading to black because "won't someone please think of the children," or turning it into a scummy festival of juvenile humor directed towards the lowest common denominator.
For what it's worth, ME kind of broke through by being one of the first AAA game series to try to include sex and relationships, stumbles and failures aside. It was the first to lay serious claim to a gap in the market, and it attracted a lot of serious attention.
I like a lot of aspects of ME, but the shooting gameplay wasn't so good as to warrant much conversation three years later when there are literally hundreds of other cover based shooting games out there.
Maybe there will be cool colonial options or new features we don't expect, but there have been little in the way of clues given to us on that front by the developers. So, while they wait, people fall back on the things they like about the series that set it apart.