I might when they get a bit older. My oldest is 10, which is a bit young I think.

For what it's worth, I play 18xx with my girls and they are around that age. It's just a matter of not stretching things out and going one turn per day, which seems to work naturally with Diplomacy

Good point. What WOULD be the minimum age recommendation for Diplomacy ? A kid would have to be ready for blatant manipulation and mendacity.