Has Competitive Dancing Improved I'll say it has.Find your way to the World Professional Latin and Ballroom from the Royal Albert Hall in London 1963.I doubt if the winners would have got past the first round today. The Posture was lousy. And that dropped right elbow might be forgiven . In those days the man's right hand used to be below the ladies left shoulder blade instead of as is today where the the ladies armpit is resting on the man's wrist just above the thumb.

There is no comparison .Compare any clip from around the 60's ( they are black and white ). Then Google Dapenda's Channel. You will be looking at Bizokas and Demidova dancing a Waltz International Style to Brian Watson singing Amore Musica. It is very noticable about the man's right elbow being held much higher which gives a bigger right side when compared with those olden days.
As for the Latin. In the 60's was pretty ordinary and in some cases laughable. Imagine men wearing tails and the ladies in a dress which resembled a Bell Tent. And that Cha Cha and Rumba Has it improved. Just look for yourself.