How important is raid comp for late-stage CE guilds?

Is there any information on late-stage guilds Cutting Edge (Mythic Sire) completing CN and other raids in a non-meta comp? I realize the World First raid requires the best specs at the time—but do you find that continues after the fact?

Heroic comp doesn’t matter at all—where does that line fall for CE?

I am not considering the world’s best raiders who sell CE Sire kills. I am referencing guilds who progress normally in Mythic CN outside meta comps.

Without going over an overly complicated answer, it depends on the tier and depends on what that person (as in the spec) in those WF comps were there to explicitly do.

Most, if not all damage and HPS checks will be non-existent OR significantly easier and can be accomplished by anyone, but if an explicit utility is needed those are harder to come by. P1 Sire for example, you’re not going to need as many classes or NF that can outright bypass having to do cleansing soaks and you can compensate that through the HPS, but you still have to keep things like that in mind to make sure you don’t lose to many. Melee and ranged balance is another item, because the fight favors ranged a bit more than melee in P2 specifically, there are limitations to how many melee you can and should bring.