You don't need virtual dice for a good RPG.
I admit and do not feel as though I am alone on this, that no one expected the majority of Mass Effect 2 to cover what most would consider side missions. These recruitment and favor missions are far less grandiose than the usual sledge hammer approach taken by most big budgeted games and the summer time movies they often emulate. This is what hooked me about Mass Effect 2, it's modesty. Choosing to focus on the relationships between the cast and the player make this Bioware's best script to date. The story's breakdown to these little vignettes allows the game more space to delve into the depth it so earnestly wishes to share. I believe the intentional result is very similar to a collection of Star Trek-like episodes and benefits like most serials by being able to suck you in, satisfy, but leave you wanting more.
That said, I have a handful of nit picks that must be addressed. Firstly, the over simplification of the character skill tree removes any sense of growing power. You can remedy this by switching up your teammates for battle, but you rarely feel like there's much behind the shooting other than pulling the trigger. Secondly, although a lesser issue are the cities you investigate. You will notice how few there are and it doesn't help that they are not particularly vast. This is something I wish the team had pulled the stops on.
All in all Mass Effect 2 and the thirty hours of gameplay it brought me have been a hearty and engaged adventure which I feel is a pretty strong lauding for a experience limited to your living room. The sci-fi genre has deservingly been treated so far this year.