One interesting angle is that hardly anyone seems to worry about Percy Harvin returning kickoffs. In fact, it's something we really, really like. We know he's got the skill to break a big one at any time, and that almost guarantees points on the board.
With Earl Thomas on punt returns, we may have a very similar situation. He returned one for a few yards and the other for 59 yards. If he can do this fairly consistently, that's probably 4-5 points added a game on average, and the possibility for a whole lot more.
When the difference between the Seahawks' offense last year (which we complained about heartily), and the Broncos' all-time record-breaking offense, is about 10 points per game, adding even a field goal per game is a significant improvement.