▲这是一个有趣的问题。我个人的看法是：英语习惯上要有 long-awaited（长期等待的，翘首以待的，期待已久的），一般不用 long-waited。事实上，你在许多词典可以查到这个复合形容词，如：
1.《柯林斯高级英语学习词典》第5版：
long-awaited adj. A long-awaited event or thing is one that someone has been waiting for for a long time.
2.《剑桥高级学习词典》第3版：
long-awaited adj. having been expected for a long time:
3.《朗文当代英语词典》第4版：
long-awaited adj [only before noun] a long-awaited event, moment etc is one that you have been waiting a long time for
4.《牛津高阶英语词典》第6版：
long-awaited adj. that people have been waiting for for a long time: her long-awaited new novel
▲但你在以上词典或其他词典查不到 long-waited 这个词。
这里之所以要用 awaited，我觉得主要是因为被修饰名词与它有被动关系，所以要用及物动词 await，而不用不及物动词 wait。比如：
a long-awaited letter
= a letter which is awaited long 期盼已久的来信
a long awaited autobiography
= an autobiography which is awaited long 令人期待已久的一本自传
注意体会以下各句（均摘自原版英语词典和语法著作），被修饰名词与awaited之间均具有被动关系：
Her long-awaited new novel is finally being published. 她期盼已久的新书终于出版了。
Opera in Britain is enjoying a long-awaited renaissance. 在英国戏剧正在复兴，这是人们期待已久的好事。
She has finally delivered herself of her long-awaited third novel. 她终于出版了她期盼已久的第三本小说。
For many, their long-awaited homecoming was a bitter disappointment. 对许多人来说，他们期盼已久的还乡之行却令他们大失所望。
Several long-awaited videos will finally arrive in the shops this month. 几部让人翘首企盼的录像片终于将在这个月到货。
They’re now shipping their long-awaited MS-DOS version of the X-Window System. 他们现正推出期待已久的X-Windown系统的MS-DOS版本。
Last week the commission published its long-awaited report on the problem of teenage pregnancies. 上周委员会公布了人们期盼已久的关于少女妊娠问题的报告。
Present tonight at the long-awaited opening of this film are a whole galaxy of stars from the acting and musical professions. 人们期待已久的电影首映式今晚举行，一大批影星歌星前来捧场。
▲顺便说一句，我在 BNC（英国国家语料库）上输入 long-waited 查了一下，没有查到了一例。但在英文版的 China Daily（中国日报）上输入 long-waited 查了一下，倒是查到不少例证。因此我们有理由认为China Daily 上对于long-waited 的使用是不妥的，至少是规范的！或者我们也可以认为这是中国日报对 long-awaited 的一个想当然误用。

【说明】刚提交完解答，看到刘老师已早两分钟给出了很好的解答！我的解答仅作参考！