Wandering Aramean has an outstanding post detailing the revamped JetBlue TrueBlue program. All the details and plenty of analysis.
Bottom-line is JetBlue is going to a revenue-based program, rewarding points based on spending. But with plenty of spending threshold bonuses, and eliminating the expiration of credits as long as you fly every 12 months or use their co-branded American Express card.
It isn’t a compelling program for me to use, but it may actually be a better program for many members than their segment-based credit model. Although folks flying plenty of deep discount short hops and redeeming for more expensive trips will see a deterioration in value, unsurprisingly.