Hmmm... I would say if the previously identified mechanical issues were directly related to what caused the plane to have to land, I think more explanation is due from Delta. This is a big plane on one of Delta's most important routes. The planes are also all old. If Delta is not able to property maintain those planes, it's an obvious safety/reputational risk.

Compensation of 20K is just on the high end of Delta's standard compensation for mechanical / other delays. 30K-50K seems more appropriate to me given the seriousness of the incident