As someone who loves choice based, narrative drive action RPGs, I legitimately couldn't care less about my specific choices being reflected in a live action or animated adaptation. My Shepard was mine. Couldn't possibly give a damn if Bioware decided that the actual cannon Shep was a female Paragon, Earthborn Soldier that fell in love with Liara instead of a male Renegade, Colonial Vanguard that wanted to put a ring on Miranda. It's their property and doesn't detract from my experience from the games nor would it deter me from watching and enjoying the film/series. The constant would likely be the cast & the main antagonist. Seeing the Reapers alone would be cool.
I'm also fine with them opting to create an original story in that universe. It's huge. I do think it's disappointing that they often hesitate to adapt the actual original source content out of fear of upsetting man children who didn't envision the main character being a woman or having a different romantic interest. I'll still check for this because it's more Mass Effect either way.