Why do we still have this terrible ranking system?

I am currently playing on two accounts. This account was d4 at one point, but is now p5. The other is d4 with 75lp. Apparently, for some reason, this account has a very low mmr and I have been being matched with others with lower mmr. My other account, however, have been being matched with higher mmr and I have a positive w/l ratio on that account. The accounts are identical in every aspect. At this point, there is no redeeming this account because of the slippery slope due to the lowering of my mmr.

Can we please, for the love of god, revamp this ranking system? I don't want to be matched with players that have a significantly lower mmr because they think I belong there. And can we just not have a hidden mmr and have our ranks reflects our mmr. This gimmick is getting so old.