Ok, I'm an Australian playing on Chocobo JP, this is what I think about the Japanese and why I think their PUG is working. I clear A4S 6 weeks ago and I don't even know when I cleared A3S and it was all through PF.
The PF in Chocobo or mainly all the Japs server (since I transfer to Chocobo and was previously in Ixion), they divide each phase for parties in PF, so for example, it's your first time? Go inside a first time party, you are on the cascade phase go in the cascade party, you are near clearing 1-2% A3S? Go in a clear mokuteki party. Each week I progress through PF till I clear. I don't know about the NA/EU server but this is how the JP server are progressing through their raids.
If you are one of those people that never practice phases and just go inside the 1-2% party and keep making all the mistake and stuff, you will likely be BL and be place inside 2ch (their BL forum same form as reddit), this will make you unable to see any parties anytime soon, 1st you are lying, 2nd you are bad, 3rd you fked up. This will limit the amount of trolls inside PF and make clearing and progressing easier. Cause 90% of the hardcore/midcore raider will look at 2ch most of the time and the forum in itself will have a macro list of who to BL, copy paste and you are on the list.
After finishing A4S in PF, they will most likely ask you whether you want to go with the same party next week so that you can farm A1S-A4S with ease, they will invite you to an LS and ask you what equipment you need for your main job and it will turn to a greed/need PT and thus the creation of a PUG group from party finder. The leader will ask the time and day the parties are comfortable with and done. That's why you will rarely see JPlayers asking for raid members and will most likely have different PUG groups every new raids.
This happens when I first clear A3S, the leader ask me whether everyone want to do it together again next week everyone say yes, but it doesn't mean you are going to practice A4S together with the same team, it just means clearing A1S-A3S and learn the mechanics of A4S by yourself, AKA finding new party through party finder and progress through there. The leader will also most likely make a new party in PF just to practice A4S and whether you join or not it's up to you. But you are still going with them A1S-A3S the following week, they won't kick you out of the PUG group just because you are not going to A4S with them, it's just that new guy whom they clear A4S with will just farm A4S with them and you will remain in the A1S-A3S group.
The use of macro it's the other thing, the JPlayer all have macro especially if you are a leader, some party finder leader will ask for macro if they don't have one. Usually when a party is full they will place the macro and wait till everyone know what they are suppose to do this usually leads to a 5-10M reading time where some people will ask questions about their role/positions and the what not. Cause every party have different macro this is one of the thing people concentrate about the most and will most likely wipe because of different macro, this is one of the macro example that I copy paste for A3S.
https://gyazo.com/bd98d1b981c804117bfa63c3165c2021
Cause I don't know Japanese what I usually do is just copy pasting the word with Monk or DPS in it on google and proceed from there.
You won't be BL for no reason that's a guarantee even if you are a foreigner, I see a lot of post in reddit saying that because you are a foreigner you will most likely be kick that's a 100% false information, I have been playing in a Japanese server for 2 years and haven't been kick in any DF or PF, they usually kick you when:
1st. They are trying to teach you the fight, but you didn't reply and proceed in making the same mistake over and over again, they open your search info with an E tag and start communicating with the other party members that you are a gaijin what should they do? Can anyone speak English (which the majority of JP won't or are scared with their limited English) hence the kick vote.
2nd. You will be BL when you are lying, most players will be BL if they are lying, I see these trend especially when I was in an A2S party which the party stated w8 practice and then someone think they already see others playing the gobwalker and think "yeah, I can do that" and proceed in fking up down w5+.
There is always language barrier if you an E player playing on a J server this will always be the case unless you start learning Japanese. But the good thing about every Japanese server is the way every party finder clear is generalize, meaning you won't be finding different strats, just different macro, for example A3S the place where you throw sluice or the invisible AOE line thingy will change in every party, the strats itself won't change. So if you are from NA/EU/AU go watch the clear video or guide video with an English explanation and then watch a clear PT J video with how they are doing it this will likely give you the idea on how they are doing the fight. Especially A4S no one in a Japanese server will be doing the Elysium one and everyone is doing the Lucrezia strats. TL

R Same fight, same strat, different positions. (Same with T9-T13 and not only AS)
Mentality of "Don't waste our time and we won't waste yours" comes more seriously in the Japanese server, what they mean is, why go to our party when you can find a party that suits you. Don't go inside a tornado phase to practice when you clearly aren't there you are wasting 7 people 90M trying to progress, this mentality is one of the primary reasons BL exist in all PUG groups in the JP server, they just don't like wasting time. Today I can only play till 10 and due to one guy he just wasted all my playing time because he is a liar and doing the same mistake over and over again. Personally, I love it, when the leader BL someone, meaning I won't be seeing you in most parties and I probably won't be dealing with your shit for awhile.
Full commitment of your 90M is also a must! You go inside a party means you are practicing with them for the full duration of 90M. You will struggle and scream to your lungs to get past the hand phase over and over with the same party for that full duration, if you decide to leave with no notice and just press "leave", get ready to be BL as well, meaning that the other 7 members which have been waiting for 1-2 hours PF till it reach full will once again have their time wasted by finding other players to fill your slot. If by some means, someone decide to leave, due to personal reasons they usually say it before going inside the instances "I'm sorry, I can only play till 7 is that ok with everyone?". Party will also get disband with notice, if someone found out that you are the bad egg of the party and the liar, "I'm sorry this is going to be my last run". They won't kick you personally, they will just disband party, invite the other 7 and the last remaining slot they will find the guy through PF.
If you are playing on a J server and is playing on a PC, pro tip: google translate, it will save your ass.