What is it with this forum and the cerebral narcissism at times? Can we sometimes just accept we don't know enough to make definitive statements on certain things, such as this GoD argument, however there is enough evidence to get a pretty good idea.
Things we do know- We know they should destroy threats such as Buu, we know there is some mortal level which is never explained outright further. We therefore rely on a touch of guess work, and trying to fit some of the puzzle together, as there job is never outright confirmed, however this doesn't mean that there isn't enough stuff in the manga that alludes to a GoDs job.
The mortal level in itself tells us that there is something the GoD and Kaioshin must follow to nurture and/or maintain a good universe. Gowasu tells us roughly what a Kaioshin is meant to do, and this in turn provides insight into what the mortal level likely is. Babari is the key here. Gowasu tells us that the Kaioshin exist to think of ways mortals can fix their issues when things go pear shaped. His joy at seeing the life advancing on Babari all but tells us that this planet is advancing in a way that it should be. Another thing to note is that strength has very little, to nothing to do with the mortal level of a world. Gowasu for example makes no mention of such, and Shin also states that he doesn't observe planets in terms of strength when they're looking for participants for the ToP. That's two Kaioshin we see doing their jobs who both show no signs of strength being a factor. This doesn't get contradicted when Beerus and Shin argue about the mortal ranking either. Sample size is of course small, but that's all we have to go on.
Sidra also confirms what Gowasu said about watching mortals and thinking of ways the mortals can fix it themselves, as when we see him doing his job and doing the calculations he states that "possibility of helping themselves 0%, effects on other planets if destroyed, none.". Sidra however is incompetent, and states that if he makes another mistake the grand priest will get angry. The fact a GoD can make a mistake therefore confirms that they have some rules to follow, which surely must be not destroying a planet with a high mortal level. This also keeps a balance with the GoD and the Kaioshin.
Beerus appears to get by on dumb luck, or the fact he's always sleeping means he's had little chance to do tremendous damage. Or, good food is the key to a highly advanced race, so by dumb luck he's got by okay, and if he was awake to deal with threats Universe 7 would be the supreme universe.
