I would've like my decisions in past games to matter more, seems like the only the ones that matter in the slightest is weather or not Ashely or Kaiden died in ME1 and how you handled Tali's loyalty mission in ME2.
As for the ending sucking. It's not so much that it sucked, as it is there isn't any closure. It's supposed to be the end of Shepard's story/series. They could've done some text summaries ala Dragon Age to explain what happens to your companions/rest of the galaxy
with the mass relays getting destroyed regardless of your ending, it would be nice to now what happens with the other species in the galaxy.