its quite simple--- very small % of people have more luck then big majority. But this its normal, because if everybody have luck with dices, then we will have all sergeant and lieutenant ranks, because then you will dont have Generals and Brigadiers and colonels.
Strategy are very limited here,usually high ranked people, make teams and targeting inexperience players, who dont know how to play, so that they reduce bad luck dices against noobs. Of course you have farmers to, who specialized on some complicated maps, and again send invitations to inexperience players, who dont know how to play on complicated maps.
That way this its RIZIKO,, not Strategic Game ,, because no mater if you have superior strategy, dices every time go above strategy.