I know +1's are frowned upon here, but, err, +1? But, to cater to one of your criticisms - namely that the surface syntax of lua might be a bit better. It's not bad, per se, but it doesn't quite match the elegance of the lua's semantics or it's flexibility.

In which case, the regularity of lua's semantics come to the rescue. It's much easier than most to develop an alternative syntax which compiles down to it.

Notice I said "alternative syntax", and not "other language which transpiles to lua". Because in the case of moonscript (or yuescript) or fennel - you're still writing lua. Using lua semantics. With no runtime overhead.

Yes, you get this to varying degrees in other ecosystems (javascript et al). But it seems to me that the friction within lua is even lower. Once you buy into "closures all the way down" & "use tables for everything", then no matter what surface syntax you're designing, it's still, pretty much, lua.