Is there any content ran in LFG that still requires you to know the mechs?

[SCorvids]

Except for higher stages of DB, do we just burst everything down nowadays? 
What's the status of twisted serpent with this as well? 
I'm curious if there's any benefit for me in learning some raids mechanics or if we just burst it.

[Walex]

Demonsbane, solo dungeons, heroic dungeons hard mode, "BM" and "IA" raids.

[SCorvids]

I moreso mean the content that's ran in LFG and people commonly recruit for, therefore ''we''.
IA has no coverage in LFG and nor does BM when it comes to teaming up in LFG to do said raids, back when I quit this game BT /VT (before TT release) was sometimes in  LFG, which still required you to know the mechs.

Did people completely stop doing this and just burst stuff now when it comes to alliance-type weeklies?
I don't know the current state of pleb BM either, sorry if my initial post was too vague to convey my question. 
I'd like to know which commonly ran LFG content is worth for me to study into, stg6 guides seem to exist for DB so that covers that if needed but for alliance content i have no clue what the expectations are.
If i'm required to learn whole pleb BM i'm ok with that too, but i'm unsure if it's wasted effort.
Thanks for ur answer! I'm a confused former raider.

[Walex]

I've literally pointed out all of the content where mechanics matter.

[SCorvids]

ok so the answer is that that type of stuff aint being ran anymore, got it.