> Finn used it fine for a sec, so it's proven that the user doesn't need to be trained at all in anything really.

Even in ESB, Han Solo uses it to cut open the ton ton

For one the technology for such a saber far surpasses and stands out from anything else in the Empire. But more importantly it requires the same superhuman Jedi magic to be useful (swinging to bounce blaster shots). It works as a ritual weapon / in climatic battles, but modern SW overuses it (as the Jedis in general).

> But more importantly it requires the same superhuman Jedi magic to be useful

No, Finn used it fine in defense when fighting a trooper in TFA. It is useful even without the Force. We can only blame sequels for that :P

Although yeah, when compared to other weapons at the time, they seem overpowered, I agree, never thought of that.