Yeah I think people expect too much. Was I the only one who was actually impressed playing Mass Effect 2 and seeing the game had remembered the things I'd done in the first game? I remember listening to the galactic news and hearing about how some hostages had been killed reminding me that I never had got around to that side mission in ME1. It was just a little thing but it made it feel like my choosing to ignore that side mission had actually mattered. One of the small things in Mass Effect 3 that really impressed me was during a conversation with Miranda where she admits she'd been wrong about wanting to install a control chip in Shepard. That conversation changes slightly depending on whether or not you'd had the conversation with Miranda in ME2 about the control chip. That just seemed like something that could so easily have been overlooked but it wasn't.
If Shepard chose to drink coffee instead of tea one time in Mass Effect can't people just be pleased that Shepard then had an "I love coffee" mug in her cabin in ME2 instead of a teapot? As opposed to complaining that Shepard actually accepted a cup of tea from Liara in ME3 instead of throwing the cup back in her face while screaming "Its like you don't even know me!"
Short of making ten different games within one game our decisions can't matter in a way that entirely alters the plot or the game's environment. So they have to matter in a more superficial way (like the news reports, emails and the things people say) or on a more personal level (relationships between characters, the death of a character, etc).
Obviously sometimes it doesn't work. I was personally disappointed not to see Morinth in ME3 but not many people saved her in ME2 so I guess the developers decided it wasn't worth spending the money on having her return. Seems like loads of people are annoyed about the Leliana thing, wouldn't really have expected that many people to have killed her anyway to complain about it. Decisions following through in DA2 did seem more tagged on than in Mass Effect (probably because Mass Effect was intended to be a trilogy from the start whereas Origins was a stand alone game)but there were still some quite nice moments like seeing Alistair again or how Isabela remembered her time with Leliana and the Warden. But then I actually enjoyed Dragon Age 2 so I probably just have brain damage or something.
It may not be a perfect system but its got to be better than developers just choosing a canon where the warden could end up being a male human noble who tended towards lawful good while your warden was a female city elf who tended towards chaotic neutral.
