To comply with WCAG+Samurai, you have to meet all Priority 1 and 2 guidelines, as corrected. That includes Guideline 3.2, which requires valid code (“documents that validate to published formal grammars”). We know from experience that a document that is valid HTML may still be inaccessible. The classic example is a page that uses tables for layout. A more relevant example is a page that has valid HTML but poor semantics (e.g., every block of text is marked up as a paragraph p, even if the text is really a list or a heading). We cannot really criticize the W3C for omitting document semantics when WCAG 1.0 was written in the late 1990s, but we must correct that omission now.
Under WCAG+Samurai, not only must you write valid HTML documents (with valid CSS), you must use the correct semantics for your content.