Party Finder for EX trials has 3 notable issues and is why I detest FFXIV's pug scene so hard that I just don't want to do the content even though I generally like most EX trials in this game and I hate how boringly easy the MSQ is.
1: If you miss the first like 2-3 days of PF progression, you've missed probably all the decent pug stars of your data center. They're off to their own farm parties getting weapons or whatever, before they fuck off to do whatever else by week 2 of release probably. Everyone else decent is in a static and knows pugs suck so they just farm in-static. Mount farm parties are not the same as weapon farm parties at all, the mindsets are just different and encourage different people.
2: Because of the above, if the patch drops Tuesday, and you jump into PF on Saturday, congrats you're now dealing with rejects who couldn't clear during the 2-3 day window, and the random casual shitters who barely can do a 24 man without dying at least twice. These people don't know their opener, they don't know how to do mechanics, they barely can tank/heal if they aren't on dps because they're used to dungeon bosses where nothing fucking happens and its just a fucking mess. They effectively just want a carry so they can go to a farm party and fuck it up, which also means even if you get your clear you have to deal with later farm parties which are almost as bad as clear parties, they don't give a flying fuck about your time or care if other people waste your time because "Its just a game, let's go for wipe 15 on the same phase and learn nothing

".
You're just fucked unless you got a linkshell, or a static, or something with people you can trust to not be mongrels that respect your time. This type of shit is why the "if you don't know the fight you're retarded" shit happens, a lot of people are fucking sick of dealing with retards who can't learn mechanics, yet want to do 100% blind prog, yet everyone else at least did the most basic homework you can do by looking up "hey what does this debuff mean?" instead of trying to actually decipher what it means yourself. The average PF player has no problem just wasting your time and are just obsessively selfish while also being dead weight at the same time.
3: EX trial mounts and the final reward they provide are a really cool reward that the community around it ruins actively every damn day I swear.
See in my experience weapon farms and mount farms are entirely different mindsets. One wants the weapon likely to do Savage easier because their are so many other avenues to get cool weapon glams and eventually a crafted version will just come out anyway that is more shiny, the other wants the glowly shiny pony/bird/dog/dragon to pose around people or whatever the fuck they want to do you saw this all the time in HW when you can just park your falcon dead center in front of Idyllshire like they've somehow done anything impressive by clearing Zurvan while not skipping Soar or Sophia EX where they got chain rezzed about 5 times because they don't know how scales work. Getting a weapon if you can clear is a fairly easy process and doesn't take very long at all, so people don't stress quite as much over it especially if this is the early phase of PF farms.
One is getting a weapon with some sort of purpose to do harder content probably and then likely has a decent mindset for clearing content, the other is a small step above the limsa afk retards who will do everything they can to flash their obnoxious usually basic bitch bullshit to the eyes of the general public like they're the best thing since Yoshi-P himself. These are not people who are usually good at the game and have a shitty mindset to boot, they have just a barely developed enough brain to do EX trials via usually overgearing and don't give a fuck about anything else. They might also be massive dps greed lords who want to kill boss fast to get mount and rage if you don't give them the best damn clear of your life, while they usually fail at greeding anyway.
tl;dr: EX trials are good content ruined by a shitty pug scene usually found in NA. JP's pug scene from what I asked is pretty good due to better attitude, less tolerance towards shitters who actively ruin parties, and a unified strat for pugs that is organized via macros.
Side note NA pug strats are almost always shit and their are sometimes 3 different ones at once because no one can make a consensus. So sometimes your prog one day doesn't carry over to the next because someone wants to do a melee uptime strat, sometimes they want to do the most safety gloves way of doing the mechanic as possible because they're allergic to doing anything that requires decent positioning the boss doesn't outright force, and if it is a very weird phase you might see some shit that just doesn't make sense. e8s is a very good example of why pug strats suck.