If I can read through the mess, you seem to be saying you can't evaluate PNaCl, so you'll just make airy and overconfident assertions about it. Even on HN, that doesn't fly. -1!
When I challenge your further assertion that something is "easily integrated into any browser", you switch subjects to arguing for prototyping and developing a complex system before standardizing it. Good idea (but beware the difficulty standardizing it late if simpler evolutionary hops beat it in the meanwhile; more below on this). However true, that is a dodge, it does not excuse your assertion about "easily integrated".
Doubling down by citing "the DOM" as if Pepper were only about OS and DOM APIs, or as if even just the DOM implementations in different engines had enough in common to make interfacing from native code (not from JS, which is hard enough even with a decade+ history of written standards and market-driven interop testing) easy, just repeats this bad pattern. So -2.
Then you seem to confuse ES4 with Harmony (which I made clear came about after ES4 failed). -3.
At this point on USENET, you'd hear a plonk. But I'll close with one more point:
Mozilla and Google using LLVM does not equate to standardizing PNaCl. Pepper is one problem, a big one, but not the only one. Consider also the folly of using a linker-oriented intermediate representation for a shelf-stable Web-scale object file format. See Dan Gohman's "LLVM IR is a compiler IR" post:
http://lists.cs.uiuc.edu/pipermail/llvmdev/2011-October/0437...
Shortest-path evolution usually wins on the Web. Trying to standardize PNaCl -- including Pepper and LLVM IR abused or patched into shape as a long-lived object file format -- is an impossibly long, almost exclusively Google-dependent, path.
Extending JS among competing engines whose owners cooperate in Ecma TC39, via a series of much shorter and independently vetted and well-justified (by all those engine owners) path-steps? That is happening in front of your eyes.
You may not like it. You may want to say "Go home, evolution, you are drunk":
http://wtfevolution.tumblr.com/post/40659237456/this-pelican...
But it would be foolish to bet against evolution.
/be