What makes a language good?
French is a language that is kept pure by the tight control exercised by the French Academy. It has a unique, pleasant sound. It does have weaknesses, such as the lack of phonetic spelling. But is it good? By many measures, yes. Is it successful? Well, it's not dying, but it's not exactly taking over the world, either.
English is nearly the opposite of French. English is promiscuous, allowing in words from any language that is convenient at the time, and even new made-up words. New words and syntaxes become standard just by being used by enough people. Is it good? Well, it does the job. Is it successful? Yes, certainly, it is a language considered essential in many countries. It may be that the very lack of purity of English is what has made it so successful.
JavaScript is more like English than French. It's not pretty, but it works, and it's everywhere. Many people are trying different things with it, different ways to construct useful software. The very lack of enforcement of structure and looseness of the language may be what accounts for its success.
So is JavaScript good? There is already a massive amount of JavaScript software out there. Much of it is shoddy, but there is a steadily growing amount of high-quality software as well. Measured by that standard of how useful it is, I'd say it certainly is good.