He has adapted, found his own slightly different methods of scoring runs. As mentioned, look at Smith, worlds best, does that mean he has the worlds best technique? Does it hell, and thats clear for all to see.
All players have flaws in their technique, why focus on just Ballance?
The focus on Ballance is because lots of people want him in the team and he isn't going to be picked and this is why.
Hales has technical issues, but is being given a extended run, Root has worked hard on his, as has cook.
Look at it differently, if your boss says, I need you to change the way you work to improve and offers help. Do you say, thanks I will try or no, I am fine as I am?
How do you think your boss will reply to the latter?