The problem with Mass Effect 2 is the stupid crew achievement and the way you easily confuse having the full crew AND having the full crew trust you, which is how you can even access the decisions that will let the full crew survive. When you spend a few dozen hours playing a game and you think you just nailed the ending, only to find out that you lost a couple of your crew members because of some obscure choices you made 15-20 hours ago, it can be frustrating. A lot of my frustration with this game came from just that lousy achievement, I was willing to live with the ending because I had not met all of the crew criteria.
Fallout New Vegas at least tries to warn you. There are two major missions that only come up to hint at you that if you head towards a certain direction you will antagonize a specific faction (there is one for NCR, one for the Legion). Some people may not be able to tell that what they are doing may indirectly annoy one of the big factions, so these two missions sort of help them notice. Mass Effect 2 is a lot more subtle than this, and the ending comes as a complete surprise.