I'm not against this, it can be used to replace lots of custom parsing for WYSIWYG editors that paste HTML from the clipboard (for example what happens when you copy content from Word, or from a site).

But it seems awfully underspecified. There's no single way to "sanitize" HTML. It's essentially a filter. So we need a way to control what's filtered.

We need a whitelist of elements, attributes, etc. for this to be useful in practice.

I believe a better name for this would be "NormalizeHTML" (think HTMLTidy), and accept a filter specification.