Yeah this kind of irritated me throughout the game. Kind of like they didn't want to render separate sequences for whether you were or weren't romancing a character, so in all the cutscenes Shepard just acts a little bit like he is romancing everyone.
The other games took into account whether you were romancing someone or not and even whether your decisions throughout had been mostly renegade or paragon and showed different scenes where Shepard's demeanor was nuanced differently based upon things like that. In this game, all that nuance is gone.
Presumably cut to make room for multiplayer and exploding head animations because profitability is no longer good enough and EA wants every game to sell like CoD.
Check this out:
en.wikipedia.org/wiki/List_of_best-selling_Xbox_360_video_games Notice how Mass Effect 1 and 2 sold around 1 million copies, but CoD: Black Ops sold 12 million. Add to that the fact that multiplayer provides a persistant revenue stream for EA and you can expect every game they make from now on to resemble CoD in some way.
When so much of the budget and disc space (on the consoles) is allocated to multiplayer, something has to go. I think EVERY SINGLE THING people have complained about since the game came out comes down to this ONE issue.