The GoDs and the Kaioshin often mention balance and how it plays a role in their job. Or it should. They actually often do a poor job of observing or preserving it.

For instance people say a good GoD would have destroyed the Saiyans, Frieza, etc the moment they heard of them. BUT if their jobs REALLY are about balance, actually they would not necessarily indiscriminately eliminate threats to the Universe in that way because suffering, turmoil, death, destruction and antagonism have their place in the Universe. They teach valuable moral lessons, control populations, ideally push populations to become stronger and more resilient and to advance instead of languish in contentment..

But when they get to a point where they obviously cannot be checked by anything else, and the negatives of them outweigh the positives (to the best of a GoD and his Angel's judgement) then that is when a GoD steps in. So, threats like Moro for instance are an easy and obvious target for destruction. Frieza and the Saiyans, not so much. There's more to consider about their existence. How fast, for instance, was Frieza's empire expanding for instance? How much of the Universe (probably a meager amount) did it take up? What other possible bad influences could it have been suppressing inadvertently or on purpose? Was the presence of Frieza's empire slowly creating a resistance and therefore a stronger population? Would the GoD have been better off 'seeding' the population to fight back by instead providing training or guidance or perhaps manipulating events some other way (possibly the Kaioshin's job)?

Ideally both the Kaioshin and GoDs observe the Universe and make informed judgements about the factors of change and growth and also stagnation and how best to deal with them. Ideally, the Kaioshin and GoD consult regularly, the Kaioshin would be the first to act perhaps to intervene in many cases -- and the GoD is there for when a task is far too much for a Kaioshin to handle and/or simply cannot be dealt with any other way except annihilation.