Not really. Almost all websites obfuscate/minify their Javascript now, making manually interpreting the code much less than "trivial." I think WebAssembly will be no worse to figure out than obfuscated Javascript.
Minified Javascript is pretty easy to turn back into something moderately understandable just by "prettifying" it. I do this all the time. It works pretty well because it started as Javascript, so turning it back into Javascript has a relatively clean mapping. WebAssembly will have started as some other language or even as no language at all - there may be no mapping back to anything Javascript could represent. It will be much closer to disassembly of machine code, or Java byte code, which is possible but challenging enough that most ordinary developers never do it.
https://github.com/WebAssembly/design/blob/master/Polyfill.m...
"The WebAssembly text format, which is designed to be read and written when using tools (e.g., assemblers, debuggers, profilers), is specified as a textual projection of a module's AST."
This is apart of the MVP even. I think the authors of WASM actually agree with your opinions here and are working to a system that satisfies that concern.
BTW taken from, https://github.com/WebAssembly/design/blob/master/MVP.md
That's very reassuring - I hope it works out that way.