1) The red state/blue state divisions haven’t been redrawn.  There was simply a general shift across the board away from the Republicans and towards the Democrats:

Update: See also More on the shift from Republican to Democrat.

2) Nate Silver, at fivethirtyeight.com, did a pretty good job of aggregating the polls to predict what would happen, at least for those states in the middle:

I’ll leave the question over whether Nate’s aggregation technique was optimal to the experts.