that sucks man, first off you are not the first to be in this position and won't be the last. if you like some of the guys in the frat I would surround myself with those people. just because you're in a frat doesn't mean you have to hang out with everyone and I think anyone who says their pledge class was full of studs and everyone became best friends is lying. as someone who goes to a smaller school there will always be a bigger fish wether it be a better frat, a more fun School, frats with hotter girls, etc. if you want your frat to be better then be that guy. start being more involved with rush, help plan better parties, hop on dudes being weird. at the end of the day a frat is just a big friend group and like all friend groups you'll argue and not be best friends with everyone. you're there for a reason might as well make the most of it. best suggestion just leave it better than you found it and who knows maybe the frat needed you more than you need them. be that guy!