Uniques in POE are supposed to be UNIQUE, not better, fluffed up and fancy rares. Some are just fluffed up rares, yes, and others are simply leveling items, but the majority have UNIQUE modifiers on them that cannot be gained anywhere else in the game, and as such can be build enabling. What you're thinking of is something along the lines of Legendaries from other games, which are the super GG items that have no better equivalent and are very rare.

For future reference, any characters in temporary leagues will be returned to their parent leagues, regardless of whether or not the game-play mechanics are being transferred to the core game. However, any League Specific items that you have in your stash/characters will also be transferred to standard, once again regardless of if the mechanics are going to the core game. This means you now have LEGACY items.