That's only the case right now, because they literally all have to be designed to have a 2-minute burst or their aDPS falls off a cliff.
As Valence said, if we're no longer shackled to the party buff window every 2 minutes then rotations no longer need to revolve around it. We could have 60 second bursts, 90 second bursts, 120 or jobs that completely rely on sustained dps again.