Canvas is more capable than Flash, it’s supported by everything already, it’s well sandboxed, it’s apparently faster than the alternatives, the technique in question now has the backing of a powerful industry leader, and the underlying technology is an open standard so it’s even got moral high ground.

And it’s possible we only managed to escape Flash-hell thanks to the fortuitous self-interest of Apple, so let’s not be complacent by assuming we’ll escape the next trap.

Having said all that, I actually like the idea of separating web applications from web documents and I don’t at all begrudge web application developers from doing what it takes to improve their applications. I just know it will be abused. The best I can hope for is that it leads to some re-focus on HTML as a stable and finished document language.