I've never seen any discussion of the morality of lending at interest in occult literature. My own take is complex, and sees that as an inevitable evil that emerges over the course of a civilization's life cycle and plays an important role in bringing the civilization down. I don't think there's much likelihood that lending at interest can be replaced by some other mode of allocating collective capital, for the simple reason that the wealth and power of the ruling classes of our society depend on their control of capital and they can therefore be expected to fight like rabid honey badgers to preserve the system that maintains their power.