The thing that makes more sense for 'ruining' is ruining replay value. One of the most potentially exciting things was playing the series from start to end and seeing just how differently things could go. As is, just on that basis it doesn't seem like there's really enough variation to justify how much time that'd take, versus any other (mostly) stand alone choice driven RPG. Mind, the DLC COULD change that, but it can only do it by so much: you're still going to have the feeling of being largely cheated when things happen like
another Rachni queen being pulled out of nowhere so one mission can still happen, and remain largely the same. Not that there ISN'T an effect, you can't exactly get this new queen to join you, and when you're doing a full paragon/'perfect' run and see stuff like this without knowing the alternative it's VERY satisfying.