milt I would agree that most errors come from a duff static system but I would say that there would be a greater error caused by yaw than there would be caused by pitch. If you point the nose up the aeroplane climbs maybe the pitot isn't pointing in exactly the direction of flight but generally it's pretty close. Same for pinting the nose down. In yaw however, the pitot head may be pointing 20-30 degrees off the line of flight which is quite significant.
Classic so how would you land a Tiger Moth? I have nothing like your level of experience but I fail to see what is dangerous about a properly executed side or forward slip to the threshold. I fly an ancient Auster with an equally ancient engine. I far prefer to be high and sideslip into the approach secure in the knowledge that if my engine did quit at the last moment I could safely reach the field and not be picking myself out of a pile of crumpled fabic in the undershoot.