I'd disagree. Minified JS source is about as "open" as LLVM bytecode - you won't read both with your eyes. And they are both standardized, have FOSS implementations etc.
> Low level memory access, pointers and the likes are the 'horrors'
It seems that everyone are missing the main point of PNaCl. PNaCl is NOT a tool to give programmers a headache with manual memory management. It IS a tool to give them ability to write in Python, Ruby, Perl, Haskell, Go, C++ and so on - in any language that can be compiled to LLVM bytecode. And mix them to their heart's content.
> This seems to imply that the browser should have a compiler that complies the low level bytecode
There are many obstacles, unsolved problems and distractions (like x86-only NaCl), but the overall direction is right.