The fight then and the fight now is definitely comparable. The rate at which the NPCs go down can definitely be compared. The fact is, Raest would indeed go down much faster (ignoring the StM strategy in Legion 7.3) than he does in today’s release. The biggest complaint today is that Raest goes down too slow from his massive health pool.
I’ve watched your videos. You’re very good, but you just barely complete the encounter even while using all the consumables you can. Even other pros today post videos of themselves completing the challenge while just barely making it to a rune or getting lucky and not dying from a Hand from Beyond cast (all defensive cooldowns not ready). This was rarely the case in old 7.2 videos of the encounter from other players. They were not relying on drums, flasks, potions, to have a mere chance to completing the challenge. They were providing an edge to the player.
I would say the shadow priest challenge in Shadowlands is worse and you are not making anything better by ignoring the past.