I don't think Mass Effect "Grabbed you" in the opening moments. Heck, it was actually alot of reading and listening for the first five minutes of the game. And looked how that game turned out.
Oh man, I loathed the opening to ME1. It was literally so bad I didn't even pick it up again for a whole year. Ultimately I ended up playing through everything, like I did for the sequels, but it totally wasn't worth it outside of the main quest missions. The opening really summed up the game: great core story and characters but everything else was mind-numbingly boring and lazy/under funded. Fortunately that problem evaporated in 2 outside of the resource mining, but if I could do it again I'd just skip the first game and open with the interactive comic from the PS3 version of ME2.
And two went from good story and characters to streamlined combat and smaller scale of galaxy. I wanted to live in this world and enjoy it. There for I needed to learn about it. Why is reading such are hard thing for people to do nowadays?
It never felt like a Skyrim sort of game to me. When ME1 worked it was through the mostly linear main story missions and talking to your crew. Outside of that you were force fed a Milky Way Encyclopedia via the Citadel, sent roving forgettable planets in a physics defying death trap or doing side missions that featured the same two maps with some boxes moved around.