<table> has a meaning. It expresses recurring, orderly relationships between <th> and <td> elements. It has always been incorrect to cram in content that isn't semantically linked that way, purely to exploit a typical rendering of it. It was incorrect even when there existed no supported way to request a similar rendering, though that was a reasonable excuse if you only cared about appearance.
Will all existing C++ code be 'incorrect' once C++0x is finally released?