Lead Designer Jeffrey "Tigole" Kaplan was on the forums recently where he gave out the good news. However, like any major change, Blizzard will have to take quite a number of things in consideration: Yes, we're planning on speeding up leveling in the 60-70 range. Keep the feedback coming. We are still adjusting it. Let us know what levels you are in what areas in this bracket.
As to why this is being done, it can be assumed that these changes are being made so that more people can enjoy the new high-level content Blizzard plans on introducing with Wrath of the Lich King.