I'm one-shotting enemies left and right with my revolver on very hard and i haven't even invested in gun damage, so i can't say I recognize the bullet sponge aspect of things, except on bosses (though i've used my crappier non-lethal gun for those), which, well, they're bosses
Granted, that revolver has a silencer which increases headshot damage, and i specifically chose it for its high damage per bullet. Plus a couple of my stealth skills increase damage when stealthed.

Between that and my breach/quickhacking skills, I tend to annihilate everything before it even turns into an actual shootout. Though, on the occasion it does, I switch to an assault rifle and still don't really feel like my damage is small-time compared to their health.

All of this against enemies that are around or below my level, of course. I mostly avoid stuff above my level, and the one time I did a quest that was red at my level, I stealthed through it.