There's nothing wrong in trying to impress general public who has no deep knowledge of classical music.
Pianists, and performers of any instrument have done that forever. Many of the "legends" we worship today did exactly that in their young years. Some of those didn't have no internet, many not even TV or radio or recordings. But you can read historic comments of they doing some bizarre circus-like acts when playing virtuosic pieces, such as HR2. It attracts people, it makes for a living and after several years, it makes a legend. Just think what you heard first of Cziffra.
At the end of the day, I think that's actually healthy for us all: the more people that gets attracted by the circus, the more people that will get interested for piano playing, the merrier. It's not that modern world gives us too many job opportunities as is, or that this is improving.
The part I find funniest is that many people seem to attack Lang Lang's musicality based on the exaggerated facial expressions and body movements onstage. "It attacks the performer icon, it is away from the stick-in-*** paradigm, so it must be non-musical, can't be good. He's a clown".
I don't particularly enjoy those exaggerated movements, personally. I wouldn't follow that as a model. I don't think they give the performance anything.
But yet, I *love* the fact that he can break stupid rules and still present an outstanding performance. I don't think he'd be any better if he'd stay still.
And also, I believe that if an audience isn't capable of focusing on the music, it's probably of the 'entertain-only' type anyways.
Topic: A really not so bad performance by Lang Lang