In Aldur's defense, he seemed a bit more plugged into the grand design than the others and realized that the original intention was for Eriond to come along and take over all the seven races, so he decided not to be a practice god for the future worshippers of his unborn sibling.
I know, right? And then after they leave, there's at least 3,000 years and no technological advances! And no societal upheaval, like the fall of the Roman Empire, to explain it, either.
At least Issa could step in when his minions were running amok. Nedra seems to have been all "talk to the hand" when his followers were genociding his brother's people.
With Torak, I think it's more like the madman who's waving a torch around on a fuel tanker. He's so indifferent to the consequences of his lunacy that it actually gives him an edge over the more sensible ones who don't want to see everything burn around them, so they back off and roll with the long-term plan of waiting the inexplicable millenia until Garion is born.