The suicide Mission is actually one of the few instances in that game were choices mattered for mroe than flavor text. Still to get the everyone dies ending you would need to be deliberatedly incompetent and the next game doesn't even register it.
And of all the characters that can die in the suicide mission only 2 play any major role in the next game and another is a squad member T'ali, Legion and Garrus.
EVEN THEN, Legion's role would be replaced with an exact VI copy of him, and T'ali's would just be a generic Quarian scientist. Garrus didn't have impact on the plot and all of the choices all became points that worked on a threshold system rather than actually having independent effects on the final battle. Every character regardless of actions and class gets to the same plot points the same way, by fighting a bunch of dudes.
Not even Squad Member selection had any effect on missions, they were only muscle and had some occasional flavor dialogue.
I like playing the games, but I would never ever call them RPGs.