The idea that debugging tools should determine how Javascript is generated or written baffles me. It's only been over the past few years that we've had any credible Javascript debuggers. The debugger builders will adapt to whatever the developers use. The horse pulls the cart.
I think a major step in the development of complex javascript apps was the development of real debugging tools for Javascript. Prior to that, the barrier to a complex JS app was too high for the hobby developer.
It seems logical that developers will prefer a language that has a good toolset. There are certainly languages I don't develop in as much due to the lack of a compelling debugger (e.g., Lua).
In the case of Javascript though, I don't think many developers were asked if they liked it ahead of time. Really it seemed like it was targeted for the much wider audience of "latent developers" who'd never used a debugger at all and wouldn't know to expect one.
This probably contributed to why it took so long for such debuggers to arrive.
The solution to this issue is already arriving — source maps. They're already supported by Closure (which, incidentally, is part of the ClojureScript compiler toolchain), and Mozilla and WebKit have it on the roadmap for their respective projects.
The browsers are working on a generic solution by providing a way to set source-to-compiled line mappings for the debugger.
Even without special support, depending on the compiler, sometimes it's not particularly hard to debug unless you're really not familiar with JavaScript. I don't think it's as big of a deal as people make it out to be.
The critical issue, as you identified, is debugging -- whichever language solves this will probably win the space.