>>36764688>Route 11, Village Bridge, Route 12, Lacunosa Town, Route 13, Giant Chasm, Undella Town, Undella Bay, Undersea Ruins, Route 14, Abundant Shrine, Black City/White Forest, Route 15, Marvelous Bridge, Royal Unova, Challenger's Cave.>unlocking like 100 other non-unova regional pokemon (yes this is important)>all the new areas have higher-level trainers.also BW2 is pretty much the best designed game in the entire series if you only care about beating strong trainers with your favorite pokemon, all of its content is not focused on stuff like contests or the gimmicks of the Battle frontier, but just having strong trainers instead (Tournament, Subway, Black tower/White tree, Cynthia/Rivals/Champion rematch, E4 rematch, N rematch, highest leveled trainers of any post-game up to lv85, etc)
comparing BW and BW2 to emerald is insane, the games are around the same level as platinum, if not bigger, the only other games that compare are HG/SS but that is because no one can agree that kanto is post-game or actual part of the series.
this is why HG/SS, Platinum and BW2 are considered "the holy trinity" of biggest games.