Iris is actually showing content from anyone that your social network has interacted with, without regard to the follow distance. I can change that, and make the parameters configurable.
Discussion
The current policy already works quite well, but sometimes unwanted content swims into your social network.
Is “your social network” the defined as the people you follow?
One of the interesting things would be to make ranking more configurable and separate, so that we can play with it easily.
One example is that I would prefer to see posts from people where I like them more often. But there are a lot of ranking choices to be made, and A/B testing is super important (having multiple ranking algos and switching between them would be even cooler, but I know that it's not the highest priority in client development right now)