I agree, very few of his powers were used in this movie. All my friends and I were wondering what happened to his Spidey-Sense - it clearly would have "gone off" many times in this film but it was just ignored.
The asteroid "quietly" hitting the gound near Peter and MJ was dumb and too cooincidental - how the hell can a chunk of asteroid hit the earth 50 feet away from someone and NOT send you flying?? It would have made perfect sense for it to hit the ground further away, and out of natural curiosity they would have run over to check it out. THEN the black gunk could have secretly made it's way to them.
This movie was full of impossible cooincidences, which really was just sloppy writing.