Character death means jack if you aren't attached to the dying character in the first place. (see DA2 prologue for a good example)
To me personally, a character's death means much more if that death is caused by me making a mistake, a wrong decision, not because the game's writers decreed it so. When Jock got blown out of the sky in Deus Ex, it was because I didn't find the bomb hidden in his helicopter, not because the writer decided that Jock always dies at this point. I rolled my eyes at the forced drama in DA2, but when bad things happen to characters because of mistakes I made - genuine mistakes, not "decide whether A or B dies", or "character dies because you chose not to do their loyalty mission" - then I tend to feel bad about it, even if it's just a side character.
No amount of mandatory deaths can force impact if they are not done well. It's in how it's done, not the quantity of dead people that's used. The sibling's death in DA2's prologue fell utterly flat because the scene is such a facepalmer. On the other hand, I felt affected by the death of Max Payne's wife in the first Max Payne game despite never even seeing her as a living person. Because you could see the protagonist's pain over it. That guy collapsed weeping, and didn't say stupid sh*t like "I want to be a dragon" two minutes later.
If the emotion of losing people is not portrayed well within the game, and that's pretty hard to do, there's no need to bother with killing off characters in the first place.