I highly question Mass Effect 3's inclusion on that list, but here's a rationalization:
ME3 has horrible writing, but is a highly emotionally engaging experience.
In my opinion, this is representative of video games as a whole - they are such engaging experiences, that their commonly bad writing gets overlooked or disregarded (and propagated, as the low standards are rarely challenged).
In this regard, ME3 possibly deserves a place on that list. I hate the writing, but that game was the most emotionally engaging that I've played in recent memory; possibly ever.
I think though, for historical purposes, ME1 or ME2 deserves to be remembered/immortalized.