Why do you say so? Aside from sound (HTML5 audio is a poor fit for in-game sounds) what is not good about it? Especially with canvas getting hardware accelerated in IE9, Firefox and Chrome and WebGL getting ground in more browsers (Chrome, Firefox and now Opera Alpha).

EDIT: to be clear, it's genuine question, I'm really interested in high-performant graphics in HTML5.

Audio support is a giant, basic problem. Games have sound.

Beyond that, all the code is in Javascript and out in the open, and the performance of Canvas isn't any better than Flash's software renderer.

You mention that hardware accelerated Canvas is going to arrive eventually in certain browsers, but hardware accelerated Flash has already shipped (as of last week). As well, Epic announced that Unreal Engine has been ported to the platform.

Aside from doomlaser's answer, have you seriously seen a single demo in HTML5? As I've not seen one yet that doesn't stutter or crash. Even in Chrome with v8.

HTML5 is like 5 years behind Flash in terms of performance.

Also writing in HTML5 at the moment is like being given the total basics. Canvas, as an API, sucks. It'll get better, more libraries will come out, but god-damn it feels like moving backwards to take a step forwards.

You mean like this? http://chrome.angrybirds.com/

Coming from a HTML5 community, I can say that our games have evolved pretty quicky (audio + visual). We're getting closer to Flash in terms of performance, tools and support.