Well a feature based luck is not a real goal, because whether u achieve it too fast (and game gets boring) or you’ll end up with no luck (=frustration). With a tradeoff like giving a buff for one stat and a debuff for another i could see it as a feature, but not as solution for balancing hearthlings.
http://discourse.stonehearth.net/t/i-want-to-dismiss-my-hearthlings-or-train-stats/19602
http://discourse.stonehearth.net/t/a-small-idea-to-better-your-heartlings/17737/6
some older threads, read a bit before we start a “stat training” thread again.