Problems WIth League System

I'm sure this has been brought up before but I really don't understand why the League system is being maintained with so many glaring problems. Originally it was created because Riot didn't think an actual number for a person's rating was a good way to measure anything and was changed because, if I remember correctly, they wanted a more colorful milestone to celebrate people's success in Ranked play as well as to somehow incorporate the "League" into League of Legends.

List of some problems I have with it:

• Hidden MMR that is estimated on 3rd party sites
• Random sequences of games determine promotion (win 2 of 3 OR 3 of 5 games)
• Games being weighed drastically between players in promos/series and players who are not
• Bottle-necking players in certain divisions, e.g. Diamond 5

As for the original Elo system which I personally find superior since it does not suffer from any of these problems, the only thing I can remember Riot arguing against it was having a "number" define the player and people calling each other out for being 1800 or whatever and not 2000 Elo. Instead, people just call each other out for not being Diamond or based on their borders. I feel like Riot doesn't understand that they are creating more reasons to flame others and encouraging players less and less to be good players and simply Diamond players.

TL;DR: League system gives everyone the ability to be the same rather than having an individual number to assess them.

I could be wrong and maybe there are good reasons, but I honestly can't see them. Having been a player since S2 and experience both of these systems first hand at nearly the highest level of both at some time or another, I hope my opinion is worthwhile. I'm also curious if others feel the same way since I've been struggling to find motivation to grind through divisions.