I agree with the late Easter, my expectation is that it will start after that.
I got pushed an ad on FB today from Disney Rewards that something exciting is coming 3/20. I wonder if that will be a summer promo offer with Disney Visa. In their recent mailer they said a summer WDW offer with them is coming. I know that won't be tickets, but maybe a sign of when we might hear something about Summer promos in general?