Take a look at it seriously...
as said by odie, if a video was needed before any tryings, SE would give us a dev swift completion of every new content, ruining both the fun of new things AND the challenge of said things.
An other thing that is really fun to notice about all the "experience only, 1 death = kick", il85+ ex runs or stuff... These are nearly all created by people who got carried though them once, and then as they don't have a group and/or fail terribly at it with other people just want to get carried again for their weekly farm.
Most successful EX group I know are all under il80, and do it perfectly fine. They never watched any videos of it, nor were the 1st to kill it. They just went in and tried.
People who aren't ready to put an effort don't deserve to clear top content, be they lazy people who just want to be carried or people watching a video and claiming they are pro and know all phases of XX fight.
concrete experience : last week we carried a tank through T1-4, claiming he knew all the fights (he got the mapping at every turn, so yeah he knew them well.. anyway). He didn't want any advice, went through, got both cads and tried to live. Yeah, it seems that enrage cad is the reference now. T2, enrage mode, nothing to say (2 tank/3 heal, couldn't possibly go wrong even with a derping tank). and then T4.. I did not think we could wipe on P2. though he had watched the vids. He just had no clue of where the soldiers pop. We wiped at every new phase after that, even though we took the time to describe it phase by phase and showing positions before entering.
this week, pugging 2 dps : one had absolutely no clue about what was going on (only coil experience was a dbag getting him up to T4, and then FC memebers on teamspeak telling what to do in real time. He knew nothing). In total through T1-4, he died 3 times :
1) at caduceus, tail wipe got him while he was combo'ing. He was raised and never died again, even doing a great job baiting the tail.
2) on the firestar at 3rd mini boss. very hard to dodge with no experience.
3) on T4, he had no clue of what to kill first so on last phase the dps split too much and we wiped. 2nd try was a perfect and he even kited the dread when MT dropped due to a crit.
TLDR : you can watch tons of videos and still be as bad as you were before. You'll just have a global idea of why you died instead of trying to learn why. That makes maybe 30 seconds of reflexion/discussion. On the other hand, you can just be willing to learn and make great progress even going blindly. You do NOT need videos/guides to do content. All you need is the will to learn.