Chrome's pretty print does wonders.
It's still not as good as raw source, but I have definitely analyzed obfuscated/compiled JS without incident.
Re:From Asm.js to WebAssembly
by AriaMinaei on Friday June 19, 2015 @06:39AM
(#9743932)
Well, the bitcode is apparently an encoding of LLVM IR, which doesn't translate back to the original source code http://stackoverflow.com/questions/5180914/llvm-ir-back-to-h...
That said, just as you can convert LLVM bitcode back and forth between binary and textual representation, you will be able to with WAsm as well.