I think the bigger disappointment with ME3 wasn't the ending, it was the fact your decisions in previous games had no impact on the plot.
But none of that is bad enough that it ruins anything about the series or the previous games. I see it as more of a missed opportunity to make the series even better.
Right now I'm in the middle of a second playthrough with a Femshep. I'm trying to make it a renegade game but in ME1 you have to be really evil to get any renegade points. Execute this enemy collaborator? +2 Renegade. Don't murder these innocent people for no reason? +20 Paragon.
This is meant as a playthrough of all three games over a long period of time since I didn't carry over data between games my first time through. Right now I'm toward the end of ME1. But believe me the council is going to die.