I guessing this is just testing the waters and not wanting to shock customers during the initial rollout. I'm sure that over the next few years the price differential between peak and off-peak will increase.
Interesting side note: I tested a 5-day ticket at peak (Christmas week) v. cheapest off-peak (mid-January) to see what the cost of making it an 'anytime ticket' would be. The off-peak ticket's anytime add-on was $63, but the peak ticket's anytime add-on was just $8. That made both anytime versions cost just about the same.
So, getting anytime tickets would cost the same no matter when in the calendar you chose.
Another interesting side note: Forget all the online crowd calendars. The day-by-day pricing will tell you what WDW thinks will be crowded or not crowded (at least, overall, not park by park). You can scroll through the prices in the Spring and easily see what week Easter is and when Spring Break is in full gear just by the cost of the tickets.