I2P torrenting with a seedbox is the undeniable future. It will probably just take a year or so to reach critical mass. It’s slow now because a lack of mass.
The main relevant difference between I2P and Tor is that Tor runs on donated bandwidth and therefore can’t scale: the more it is used, the more volunteers are needed to donate bandwidth. Which is why they aren’t happy with people torrenting.
I2P is P2P so the more people use it, the faster it becomes. Which is why they really want people to use it for torrenting.