I liked how at the end, you needed to assign your team differently or people would die, but if you had half a brain, you couldn't do much damage to your team at that point. My first time through, I only lost two people (Thane, because I thought it was a good idea to make him leader of the second team, and Mordin, who often dies at the "Hold the Line" portion). I think the obvious way to fix this would have been to make the string of choices much longer, extending the final mission into a 2 hour epic, and maybe randomizing what happened to your team so you would have to adapt accordingly.
To be honest, I thought the final battle in Mass Effect 1 was much more epic. A battle on top of Illos and through the depths of the planet, meeting a strange AI, charging through The Conduit to the Citadel, battling your way on the outside of the citadel to the final encounter with Saren before finally putting Sovereign down was just plain epic. Mass Effect 2's ending seemed to have much less of an impact to it, however.
I still liked Mass Effect 2 a lot, liking it more than Mass Effect 1 (In most ways), but I hope they'll iron everything else for the epic conclusion.