I might be pulling this out of my ass, but I somehow recall that some of the wizard abilities in D3 implied telekinesis. Which then implies that psychics could be real. I think you could combine it with some aspects of like 1800s spiritualism or aesthetic mysticism to nail down the theme.

I think it would fit right in to the gritty world D4 has made. Maybe be a sect of Ivgorod, which gives us a reason to go there for the first time and maybe back to Arreat to re-settle the clans.

Edit: Oh! I also forgot to mention how it could be so environmentally interactive. Like telekinetically throwing random environmental objects at enemies or slamming enemies against walls in tight spaces.

For some reason this also made me think that whips should be a weapon class. Rogues, the psychic, & sorc could use them.

I mean they invented time travel for the shop. Why can’t they make psychics?

I think a psychic class would be cool.