A long-awaited event, film, letter, or decision is one people have been waiting for for a long time — and they wanted it. The feeling is “at last.” A long-awaited album, a long-awaited holiday, a long-awaited baby: the word sits happily in front of a noun and sounds a little written and warm. In speech people might just say “we've waited so long for this.” It is almost always positive; you are glad it finally came. Though actually, you can use it with a straight face for something people dreaded too (“the long-awaited exam results”), but the waiting is still the point, not whether the news is good. The person who waits is not “long-awaited”; the thing they wait for is.