Promos, are not effective change them.
promos are unfair, the fact that you must win 2/3 to advance. i think its not an effective way of ranking.
it should really be to the point that once you exceed 100 point, you can get promoted right away,
2/3 is a 66.6 win rate, which is high to achieve.
an alternative to that would be allowing anyone who is in promos to get higher in pick order so that they can regulate bans and pick a more comfortable possition.
also losing in your promos should get at 99 lp.
