In theory Dx12 can make use of hyperthreading so you can get more processing power out of the i7, but then the same would be true for the i3, so the i3 may be all you need in the future. Games keep flipping and flopping between gpu usage and cpu usage, it really seems to depend on the quality of the developers. As you can see from the article I linked, Tomb Raider, which looks pretty amazing, doesn't give a single s*** what CPu you have (within reason). So the devs made a game that's actually optimized well.
There's not reason to trade it away, as it's unlikely your friends will make better use of it. And it's still more powerful than an i5, just not by enough to justify it's cost over an i5.