Now that we've got puller upgrades, you can both push and pull from IC2 machines - pipes! The issue is, there isn't a good way to form a pipe line, because IC2 machines only accept items that they can process. I suggest a buffer type machine is added that has 6 slots, and can accept puller and ejector upgrades, so it can form a pipe. The sorting machine could have it's recipe changed to use it as a crafting component to form a kinda of tier system too.
The puller upgrade could do with a recipe first too, and a way to actually set it's direction