But even so, you'll probably hit some weirdness in IE6's jscript implementation.
However, excanvas was quite slow though, at least last I tried it.
Also, JScript is actually surprising good and is nothing like the DOM or CSS, AFAIK the only known bugs are Named Function Expressions being parsed as Function Declarations (http://kangax.github.com/nfe/#jscript-bugs), and a couple RegExp bugs (http://blog.stevenlevithan.com/category/cross-browser).
I suppose if you count DOM bugs, like the memory leak, that's a problem. That's where jQuery is amazingly helpful(and presumably other libraries like it).
Considering Raphael is as slow as excanvas in IE (but much faster in other browsers), it's probably IE's fault, not excanvases.
JSLint picks it up:
Error:
Problem at line 1 character 22: Extra comma.
var x = { foo : "bar", };So you would be losing the ability to have the browser do layout for you, losing the ability to scroll sanely, etc, and gaining perhaps some improvement in consistency, maybe. And maybe not.