I would hardly call it “hosed”.
You are correct that US 127mm HE pens 26mm with IFHE and 21mm without, but this hardly “hosed them”. The only significant different there is that they no longer penetrate heavy cruisers plated with 27, which means American and German Heavy cruisers in some areas.
26mm still allows penetrating of most same-tier Battleships on the extremities or even the deck and upper hull areas of some others. That’s the single most significant armor threshold for a T7 light cruiser.