I always enjoyed games that let you summon around 1 to 3 minions and more with upgrades. Something that Terraria did shortly around its 1.2 Update. I would be interested in seeing this become a new weapon of choice in this game as well. Though I am not sure how well that would work with its current roster.
It could be done with some sort of "Portable X printer" or "X Teleporter" items, or by making captured monsters more useful.
