The cold following rules where more made for balance than anything else, so that a giant player couldn't just conquere a city from a high food producing race to negate their high food upkeep and couldn't use other races troops to fill their ranks without a certain disadvantage. Well I can see it may be hard to balance and even harder to implement in the game.

I went with the young giants, because in the Norse viking cultur it was not uncommon for boys as young as 13 to join the raids, but using halfgiants or giants with a lesser amount of non-giant blood could be cool. They could be called something like: The unclean, Halfbloods or Mugglers. To show that they are weaker and looked down upon by the bigger and more powerfull full blood giants?