I think grey morality is a bit... overused, or at very least a bad phrasing. I like morality systems to a point, but it all depends on what the scale is measuring and why. I don't like having to make only certain choices to be able to actually fully complete a game, like in Mass Effect two where you have to be totally topped out in either paragon or renegade to say the right things to keep your people alive. Though, at the same time I dislike games that ignore morality as well, or at least story driven games that put you in the role of a character with personality.
And now because I feel the need to kick the beehive, there is a universal morality, its a pretty small list of things (as they apply to humans and human cultures), but there are things that people instinctively react poorly or well to, that are entirely culturally unbiased. Which basically means every human who doesn't have something actually wrong with their brains will react in similar ways to these actions unless trained to respond differently. Things like murder, theft, and cannibalism, are all met with disapproval and usually a violent reaction, because as people, as a social, thinking, societially based creatures humans understand what is good and what is bad for the entire group and will try to get rid of destructive behaviors or elements to keep the collective group safe, happy, and healthy. And that's just people, not even going into animal habits that mirror our own, or anything more esoteric and spiritual, which I could go into, but it really isn't worth the arguments over pointless semantics and petty fears that would ensue.
So my point is that morality is important for believable characters, but shouldn't be a determining factor in whether or not you can complete important parts of a game, and should really be based more on actions taken and less on dialogue spoken, because anyone can talk a good game, it takes someone with steel in their veins to make the hard decisions for the right (or wrong) reason.
And finally Selfless and helpful= morally good, selfish and grasping = morally evil, that's kinda the whole crux of morality.