The Astrodyne's design on MP being first is to guarantee AST will never run into MP issues because of bad RNG. Whether that's overtuned or undertuned is a different story, but I don't think making MP an RNG resource is a good idea.

Divination was changed to not require seals, which removed the big RNG aspect for party damage buffs in its ShB iteration. That's actually better because there's no more convoluted complexity in raid buffs - which affects parties more when aligning for burst windows.

The only difference in AST's DPS is their personal DPS. The Astrodyne's DPS self buff is most likely made to be more in-line to proc-based classes, where it's nice to have but not mandatory to succeed. Just think of not getting the seal as bad luck like DNC's fourfold feathers not proccing from their GCD skills.