The new kickoff rule has certainly generated its share of panic, alarm and bad physics.
For a look at the real world experience from ’05 and ’06 of kickoffs from the 30, see this post. Just remember, as the author notes, it’s from a fairly small statistical sample.
The data from the past two seasons does not point to big effect on the game from this new rule. However, I’m not willing to rule it out because of the small sample sizes. I do wonder about the impact of the new rule becoming a self-fulfilling prophecy. Many coaches are so concerned about the rule that they will implement changes in strategy and personnel on return teams starting with the first game, before the real effects are determined. These coaching decisions alone could be enough to affect the kickoffs and returns. Perhaps the coaches will take a wait-and-see approach.
(h/t The Wizard of Odds)