Removing global rating is just pure insanity. As Excelsior said: rating is a main driver why people play. It's like an entire ladder system and competitive logic condensed in a single number. It's the reason why people care about the outcome of a game. It's like the money at stake in poker. It's like the oxygen in every breath we take.
Excelsior mentioned a few completely logical and vital elements to rating as well: how to balance lobbies? Will optimal balance still work as intended?
There have been numerous suggestions how to fix some the flaws in global rating:
Have a map specific rating, have a win rate per map stat displayed, have a number of times a map is played stat etc etc etc.
When I brainstorm right now I can even imagine something like a "view player info" tab in the lobby that when you right click on a players name opens a little stat window with circle charts of most played maps (percent of astro, Seton's, gap) and or a list of the top 10 maps with specific win percentages to better make it able to understand a players skill, or for example a map specific global rating. I'm sure this can be computed with the data of astro, gap and Seton's and a number for all the other maps.
If I was pc I would tinker with that, I love that because I'm good at it. I've worked with quantitative analysis and have some data base coding skills.
However what ftx proposes is insane and will hurt faf, so please act like smart people and don't do it. Thanks.