Bifröst: Vikings/Kingdoms can't forge Kingdoms/Vikings special workers anymore.
Since DE, in Bifröst, its now impossible to forge Kingdom special workers as Vikings and Viking special workers as Kingdoms, worsening these buildings and limiting the forges usefulness in a coop setting with mixed clans.
As an aside: Merchant Lores and Sailor Lores also don't apply to both sides like sharp axes do, meaning a Viking clan is at a big disadvantage if they have to use a Kingdom Kröwns building as all their lores for ships and trading won't work on these.