Huraijin is effectively useless in all fights currently in the game right now. We still Huton prepull and keep Huton up with Armour Crush.

Huraijin is a weaker GCD than Spinning Edge that, if we had the button right now, would only be used to recover Huton after death without spending a mudra charge. However, the reduction in duration of Huton from 70s to 60s means Huraijin has a use in fights with long cutscene-style downtime segements like E1S, E8S and TEA: namely, giving us Huton back without spending a mudra charge. A button that exists only to help us recover from death easier doesn't need to exist when, ideally, you just don't die in the first place.

Except that you can carry Huton through all 3 of those given examples if the timer is a maximum of 70s instead of 60s. So the button feels like it was added for no real reason other than to fix a problem (dropping Huton through cutscenes) that only exists because of a change they made (Huton duration decreased by 10s).

Regarding Shukuchi and Raiju: You will not be able to dash into an AoE, Shukuchi out, then dash back into the boss with the second Raiju to keep your rotation going if the first AoE just snapshots while you're in there and kills you outright. And even if it does work, we should not need to resort to something as convoluted as that just to stay safe while keeping uptime, when they could just as easily allow us to keep Raiju if we use other weaponskills (since we can currently only use it after Raiton or we lose the procs) or change them to oGCDs. If the design intends us to Gapclose Shukuchi Gapclose, then the design is bad and should be changed.