I see. The Psycho wasn't out yet when I played it. With Mechromancer, you put a point into anarchy and raise preshrunk cyberpunk, Smaller lighter faster and Close enough to max. Put one point into blood soaked shield and you're invincible. In almost all situations (that aren't bullet sponge bosses. For those you have to move), you could literally just stand still, aim at the ground and kill everyone.
You're pretty much utterly broken at level 21, which is very early game. You have a multitude of ways to raise your damage output even higher at higher levels (There is in fact a single pistol later on that utterly breaks the mechromancer even further), but the character loses her unparalleled efficiency around the 3rd playthrough or so as her damage output gets pulverized if she dies. Not a problem whatsoever for the first 100 hours, as the Mechromancer will literally never die if you're not playing as an idiot, but you surely know how insane the highest difficulty enemies can get.