This. The tuning of the bosses they didn't test was better than the others lol. The only real big issue was the Jailer Mythic shield in the last phase and they wouldn't have tested that anyways.
Also iirc they didn't really test the fated raids? Which also turned out quite ok tuning wise imo. It's just so much better if you have to go in blind the first week and figure out tactics on your own instead of being forced to either play ptr or watch videos from it.
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Which is the way to go honestly. It makes for a far better watch experience for the RtWF too - instead of seeing guilds perform their already rehearsed tactics including already finished weak auras (!) you will have guilds having to figure out what to do in a live environment.