1. hook_form_validate_alter and hook_form_execute_alter have been eliminated. there usage was limiting and a bit confusing. now, only hook_form_alter remains
   2. replacing those hooks are the #validate and #execute attributes. these can be used either when building the form in a module, or via hook_form_alter. these attributes are built in array form, to allow for flexibility in how they are called. for example, a module could simply add an element to the #validate array via hook_form_alter if it wished to perform additional validation, or it could redeclare the entire #validate array if it wanted to override any existing validation
   3. attributes #validation_arguments and #execution_arguments have been added to allow args to be used w/ custom validation and execution functions. this are also declared in array format
   4. renamed #valid attribute to #validation. this doesn't cause any conflicts, and makes the naming convention more consistent
   5. renamed the existing #execute attribute associated w/ submit buttons to #submit