I've always had an issue with something that implies "complete stealth". My concern is that, even if it has an incredible weakness AFTER use, the potential for abuse is still an ever-present temptation.
For example (and JUST an example), using Stellarium it would be incredibly simple to smuggle a billion-ton-payload atomic nuclear antimatter aether bomb onto a planet or capital ship using little more than a few sheets of this armor and an interstellar tugboat. Not just incredibly simple, but if it is complete stealth, 100% successful and without any reasonable counter. You don't need shields or aetheric power to accomplish this task, and I worry about the balance of a metal, even with weaknesses, that can accomplish complete stealth.
This is my only concern, really.