This games biggest issue that there are huge differences in the playstyle of players and they are forced to group with each other unless you go in a pre-made.

What I propose is to bring in an ELO system to this game that ranks your individual performance and groups you with similar players.
  • If you are an optimizer and play your job at peak performance? You get grouped with other people of the same mindset.
  • If you are competent and can keep your GCD rolling? (and thus above average sadly) You get grouped with similar players who also do the same.
  • If you don't care about combat and just want to play the game? You get to play with all the other people with the same mindset.

To be fair in this system everyone would start at the middle and would go up or down based on individual performance in duties per role.

After some time, the player base is sorted out and Elitists and Toxic Casuals will never have to interact with each other again.

As an extra bonus you could set your Party Finder to only allow Rank x-x to preemptively filter and make less trap parties in PF.