I know what you mean, Samsta.
I also haven't cleared T5 yet because of similar reasons.

The problem is: you can watch 10000 videos and read 10000 guides, 1) it's not the same as doing it yourself and 2) it doesn't make others watch those videos and read those guides.
In Duty Finder you often don't even get past phase 2 because no one knows what to do OR everyone has a different strategy about how to position yourself and communication doesn't seem to help.

In Party Finder there's another problem: if you manage to get a group together and it actually says TRAINING in the PF comment, people still insult you if you do something wrong and leave immediately after one or two wipes.
I mean, I'm sorry, watching videos doesn't make me do it perfectly the first time, congratulations if you are perfect, I am not.
The last time I tried it a DPS died to second divebombs and left the party immediately. Oo
Or tanks running in after one wipe while no one is ready yet.
PF isn't much better than DF.
We only had one other person that really wanted to practice. The others didn't even talk or answer to questions if they know the strategy ... well ... 3 motivated players still aren't enough for T5, even with ilvl 100 +.