There's one... well, two... major differences in Shigure and Ushio, however.
First, Ushio isn't a "lucky ship" like the "reapers" Yukikaze and Shigure whose presence was doom for others around her, she's a "rescue ship" like Hamakaze. Ushio spent most of her service as a carrier escort, and her escort objectives (including "lucky" Zuikaku) basically always survived. She also was tugging the damaged Myoukou when she was struck by a torpedo that blew off her stern, then damaged the submarine responsible, and tried tugging Myoukou back, although she was eventually relieved by other, undamaged destroyers. (Myoukou survived the war because of this action.) Ushio also rescued the survivors of the Akebono after Akebono was sunk by airpower after Leyte, doing so at risk to her own ship from airstrikes.
Ushio has plenty of reason to be a PTSD ship, but can pretty clearly say she actually did something to save her comrades.
The second reason she's not the PTSD ship, though, is, like Hamakaze, LOLBOOBS. (Hamakaze, in fact, lasted until Ten-Go, while current super-lucky ship Hatsushimo only barely survived Ten-Go to sink in the last weeks of the war in friendly waters.) Poor girls can't get a break from being "big breasted lolis" to have a character of their own, but Ikazuchi is "loliokan" because of a similar (but more tragic) record.
That's why I often hate fandom's presentation of some characters. RJ => lol flat Hamakaze and Ushio => lol boobs Akagi => lol big-eater
You can't take "the bad" from the fandom. They both complement each other. Naturally there's some dominance, but without it KanColle is just another browser game with some official manga no one reads (if they would many could have known the Abyssals weren't the Allies representation since the very beginning, instead we have to repeat it without them believing again and again).
Murakumo-san!...Ushio-chan.Just like rice that has been reaped, you too shall be reaped before you know it...Shigure-san! Please wait!I've got one thing I want to tell you...That is why each and every one of us needs to co-operate on tomorrow's operation! Please do not go back just like that!I apologize for not mourning for the people you hold dear, Shigure-san... But I, and everyone, feel the same...!You, as I am, are called a lucky ship, spending your days in safety, aren't you?
And yet, you'll only be able to think of yourself as 'lucky' for now...
