To be honest, I don't see guilds that boost are having a massive impact on gst. Boosters always lose in the first two rounds.
Also, almost all guilds that boos gets reset and the ones who don't get caught only boosted few matches that don't even give them 100 points (if they were above 6k). If they were below 6k, their guild rating will get low because of beating a weak guild which will negatively effect their points jump.
I think the rules are fine as they are now.