I'm still thinking (and many others too it seems) that the order +3/luck -3 combos is still a very good option to take (that is unless you take a balancing mod, like the most excellent, yet simple, cherry mod).
So why not enhancing a bit further the interest of luck by tweaking national heroes? The idea would be to have all national heroes with a pre-drawn heroic ability, and this ability would always be considered as active (thus increasing with time). It would gives neat and pleasant surprises to the player, when he receives an hero, like a kind of super-surprise gift.
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Let me see, I got Ekishnugal the first king, what do I got... oooh, extra reinvigoration, how convenient it is!!