Instead of promos

You have to get an extra 50 LP that goes up and down the same as your 100,but its separate from your normal LP,if you get to 0 and lose you go to X LP in your normal 100,if you get at least 50,you go to the next division/league.

to win league placements you need 75,and yes,LP values would need to be increased if the person only gets 5 LP a game.