[Edi]

Of all the ideas in this thread, the suggestion to take away glamour is far and away the stupidest one.

It's one of the defining characteristics of the Vanir, so taking it away will just break things even worse. Increased gold and resource cost, possibly a reduction of defense and perhaps increased strength, giving them less of a stealth bonus and other such could be good solutions. Afaik stealth isn't tied to glamour. It was not in Dom2, glamour units were just given stealth +25 as a matter of thematics, but e.g. the Mother of Tuathas which had glamour only had stealth 0.

Edi