[Bug 7190] Since all "specially focusable" elements have an activation behaviour, the Action of accesskey-laden commands is to _not_ focus them if they are focusable. Instead, such elements should probably always be focused if focusable, then be activated.
[Bug 7411] :invalid and :out-of-range shouldn't match until the user has consciously interacted with the form. Roughly, after the input fires a change event. If, say, <input required> matches :invalid immediately on pageload, it becomes basically useless.
[Bug 7427] When the maxlength attribute is omitted it should return -1 like Opera and Firefox and not 0. (Alternatively it could return the maximum value like Chrome and presumably Safari do, but that seems less nice.
[Bug 7428] Safari 4 preloads media and FF 3.5 doesn't in <audio> tag; perhaps HTML5 sections 4.8.10.5 4.8.10.8 are unclear or need a 'preloading' attribute added.
[Bug 7434] Everything with role=heading should also have an associated aria-level that indicates the level of the heading. The level of the heading should probably be based on the outline algorithm.
[Bug 7441] The specification only ever uses the prefix:localName convention for some attributes in the XML namespace and whenever it does it is pretty explicit about it. xml:id is never mentioned outside this section and the prefixes svg and html are never used.
[Bug 7466] This section forbids exposing rel=feed but not exposing e.g. rel=copyright. I think that is wrong. The specification should not dictate UI for this.