Letting only user #1 pass all the validations of required fields when saving content
You could probably use hook_form_alter and check if the current user is uid=1 then make each field not required any more. 

That would be easier for most forms than messing with the actual validation functions and it would also make the UI reflect what is actually happening. You could even put a little message at the top of the form letting the user know that the form has been manipulated like that.