Julian II (the Apostate) and his policies

[Theodosius the Great]

Constnatine's dynasty may have been suucessful in changing tghe face of Late Roman society (introducing and strengthening Christianity helped post-Roman Europe a lot later on), but the seeds of destruction were there as well

Well, I wasn't even speaking in those terms when I said "successful" but simply that the Constantinian dynasty lasted longer than any other since the extinction of the Julio-Claudians.

And Constantines dynasty succesfull? In what way? Producing 3 sons and give them each a share so they can battle each other?

Speaking strictly from the dynast's point of view, it was the most sucessful dynasty in 300 years. And people tend to forget that Constantine was NOT the founder of his dynasty. His father, Constantius, began the dynasty in 293 AD and lasted until Julian the Apostate's death in 363 AD. So, 70 years of an imperial family ruling at least parts of the Empire. Doesn't that sound successful ?

Furthermore, you don't see major uprisings against the family of Constantine after the defeat of Lincinius. The armies were loyal to the dynasty. So, establishing a real dynasty created political stability. True, you had civil wars between Constantine's heirs but no usurpers are able to gain any significant support. Civil wars between two Emperors of the same dynasty is better than civil wars between two usurpers since that may lead to endless wars like the crisis that ensued during the mid 200s AD.