I think Eviscerators work wonders in enclosed battle areas like cities, hives, starships (people seem to forget those) and trenches. Not every encounter is on a plain field.
The debate about the absurdity of a TB? I don't think it is that broken, since it's an abstract presentation of what a human can handle before taking noteworthy damage. The human body is frail compared to a block of bricks, but it is not THAT frail.
Maybe it's because i met some (strange/strong/dedicated) people while training Krav Magar that i do have no problem with the mechanic. There are people out there that are literaly harder to make a dent into than others.
Oh, and yes, living tissue has other properties when it comes to weapon technology than cevlar or other materials used for bulletresistant clothes. Compare the make-up of a dumdum bullet and an AP bullet. All designed to damage/kill but with very different effects.