I just wanted to say my piece. The goo bothered me, but I feel it's a minor problem. It's what they did with the damned goo, or failed to do.
To me, goo + Engineer were the point of the entire story. That's what I wanted to see. Hell, the goo is already responsible for human life (in some form) and obviously also responsible for the Xenomorphs. That moves it from sci-fi trope to central plot hinge.
Don't want to muddle the thread, though. The Senate convening is a mighty fine idea.
Dat tea?