The entire point of barbed wire in reality is it's really difficult to walk through. Shouldn't they all slow, and then maybe the slowing one just does so more?

I'd even support 'normal' barbed wire doing no damage (presumably the biters exoskeleton is tough enough not to be torn by the normal barbs?) and then damage of any type is an upgrade.

One final thing - shouldn't electrically charged wire do electrical (or, energy) damage, or was there a good reason to choose piercing?

I'll think about adding a slowing effect to all of the barbed-wires.
As for the piercing damage, I made that confusing, as I did use "electrical" (laser) damage for charged barbed-wires, and I forgot that "piercing" was its own damage type. Will fix.

Ah, cool. Sorry, replying before I actually GOT to the charged type :)

But yes, please do think about the slow. It's the main reason I wanted to use this mod really - turrets kill things just fine, so more utility defenses are what I'm looking for.

I already have slowdown / poison mines from elsewhere, but they're quite high up the tech tree.

If you wanted to and it wasn't completely implausible, I'd be fine with barbed wire damaging and/or slowing the player as well, because it's not particularly discerning.