Evolution in taijiquan is always ongoing so any feasible explanation that makes sense has a following so all taijiquan is good as stated. All MA start with a large (open, expanded) way of doing a said form but the form is usually 'empty'. As the form becomes rote, and natural rhythm/way of form self expression becomes second memory, the individual can do what he needs with the form. Chengfu's expression was the form! In the same breath, Lutang's expression was the form (his own understanding of Wu/Hao, xing-i and baquazhang). I cannot imagine Lutang exhibiting a form in the frame of Chengfu since the body type and understandings were different. All poins of view are valid and they are followed by their corresponding camps. All taijiquan is good.
Taipei, America, France, Australia, Estonia, Russia, Italy, Switzerland, Japan, Germany. I think it is also practised in Germany and the Netherlands - probably a lot of other places I don't know about as well.