I agree with most of your points. Mass Effect universe is immersive as they come.
I have a few gameplay complaints but otherwise its an amazing gaming experience.
I do wish the action was a little bit more meaty when it its on, but maybe this last mission you speak of is going to answer my wish.
Also, the game would be really cool with coop during the action parts. I think they could have successfully implemented split screen local coop for only the action segments since you have 2 other teamates with you at all times. May as well give the option of having a second player control one of the teamates.