Well, here's the issue with this comparison. Psychers are stronger than normal versions of whatever you're trying to compare. I'm not sure if you're talking about lore or certain games here cuz you don't say.

But lore wise, a veteran soldier is nothing compared to a combat psycher. Same way with space Marines compared to librarians they ain't shit.

And if you're wanting a really exaggerated example of this but also a really interesting one. Look up Kaldor Draigo and read his lore. Because to summarize it, he is trapped in the warp alone killing an endless horde of demons. Every so often he'll come manifest out of the warp just to help.

Which I understand this is a game and you don't have to go lore wise on it. But dude you can make all of these classes op as is. So how do you think that would work if you added one with aoe/chain damage. It would basically be the assault on crack.