RANKED PLACEMENTS

Beginning of season 5 is when i first join league. It has been my passion ever since then. It is an outlet for myself, friends and other people in the league community. So after the new season started everyone was excited for the new draft mode. Everything seemed to be progressing and it started to feel like a new season. Then the new ranked draft queue went off line and people all over have been landing themselves in bronze. I know for a fact that I myself have greatly improved over the last season, only to get stuck back in bronze. Last season rank i had no clue as to what was going on and landed in bronze 4 after I lost all my ranked matches in placements. This Year i went 6 wins - 4 losses and ended up back in bronze 4. Why does this happen. I know quiet a lot of people on league and they were all silver 3 and above, but now even if they did well they are also stuck at the bottom. What kind of ranking system do you guys have running? I know there are a lot of people that feel the same way that i do and have the same question running through their minds. What happened to the Ranking system?