The major problem with the 1-50 system in H3 was that people could be boosted by accounts with bad records (for example people wanting to get a 50 would play with low ranked accounts with awful win/loss record to rank up faster). The main problem this caused was that people would purposely lose games to make those accounts. The main way to fix this would be for the ranking system to simply ignore players whose records/ranks are a lot worse than the average record and skill ceiling/floor for that match when the ranking system decides how much the winning team should go up by. For example if a 49 was playing with three booster accounts against 4 50’s, and the team with boosters won, the ranking system would ignore the boosters when calculating how much the winning teams ranks would increase by.
So in short, the ranking system would ignore outlier accounts when looking at the average account in a match, and calculate how much the winning team will increase by accordingly.