You are wrong, just look at reason why katysha get nerf, coz players can react.
Now go in cheat mode and test, what arty shoot faster from all this kinds.
Katysha are not most lethai arty from all 3 units taht are in tiers. Coz after first salvey you can retreut if you dont hear it. Now image when you dont hear PW or stuka barrage sound, you just must pray that you squads dont get wipe.
Huh? I never said that Kat is more lethal, I'm just suggesting that they seem to be designed to do different things (also, not saying that that is good or bad).
Stuka and PW clearly have a better alpha strike that is certainly more lethal to single team weapons; however, IF you survived that alpha strike (and yes, that happens), there is no reason to move your shit anymore (or any adjacent units), because that was the end of the barrage.
Seems like PW's and Stuka's intended role is to kill stuff more or less surgically and reliably. They have to have a serious alpha strike, because, well, there isn't a "beta strike". All allied rocket artillery seems to be more for area denial: As opponent, you have a good chance to survive the first rockets, but you really should move all your stuff in the vicinity away to increase chances of it not dying. And according to the notes they feel that Katy - despite probably being intended mostly for area denial - is too good in the role of the PW/Stuka.
Again, I'm not saying that Katy is too good now or too bad, or that the intended role is useful or not or that the whole concept has merits or not. Only pointing out that the argument "but PW and Stuka have a huge alpha strike" falls short.
Now, feel free to discuss if the Katy's alpha strike is indeed too strong or not, or if PW/Stuka barrages should work more like Katy/LM/Calli or vice versa, or whatever...
I agree with Katitof, though, in that it would be helpful to get like "Designer's notes" on what roles the units are supposed to fill, because at that point one can discuss to what extend the units actually fulfill the intended role and if that role is useful in the first place.