Um... Isn't comparing a 119 weapon to.... anything that's not a 119 weapon... no comparison at all?

There were no 119 GS... There is a 119 GK... and from my experience, aside from formless shenanigans where there's a heavy PDT on the mob or w/e...
A good MNK and a good SAM are kinda equal in DD.

And as to the drg... Go get Drakesbane!! Even without the mythic bonus, that beast of a WS was faaaaaar out damaging Stardiver. (ok, not super out damaging... BUT it was dealing more on average from what I've seen. And iirc, Drakesbane can crit while Stardiver, being a MeritWS, can't)

Yes, MNK is being used more... but then every other DD has kinda always out shone WAR... just by the nature of all their swanky JAs. (SAM self skillchain crazy, DRG jumping, DRK having basically the same JAs but more potent while being suicidal, etc)

And as to Delve.... I don't think MNK being used in Delve implies MNK is broken.

No more so than WKRs being nothing but SMNs means that SMN is broken.

It's the fault of the content being skewed to support only a few jobs.
Obviously, WKRs aren't as bad as Delve is with the exclusion of all other jobs... But Delve is... kinda awful at including more than 9 jobs.