Placement Placements Placements... how they could be better

So when i got done with my placement game i was mad knowing i was going to get bronze 5. So i think that in the next season and from there on out you never have to start lower than your previous rank. Placements should be more about you performance than the teams. Ex. So say you are playing talon mid and go 12/3 help with objectives and team related things, and you have a trolling team mate who is making it impossible to win and kill the other lane opponents and your team gets to far behind so you guys /ff. So then after that you're o wins and one loss and its isn't your fault and you couldn't do anything, so to fix this your placement after ten games relies more on you game play then your team. So for another thing would be a point system after ten games bronze could be 100-200 points and each rank correlates to you're point after ten games so you get 150 points you could be bronze 2 or 3 depending on you game play. So for how good you help the team you get points after the game if you do nothing but hurt the team you lose points and kda applies and placements would be less about winning or losing.