CKEditor and pasting

[Arcturus]

Probably a little late to be useful, but I ran into the same issue today, returned to this thread to semi-reverse engineer myself, and came up with the following:

Change 

$value = preg_replace('/<span.*?>/i', '', $value, -1, $qty);

to
  
$value = preg_replace('/<span(?!.*?class=").*?>/i', '', $value, -1, $qty);